如何在ListView Android中打开文本文件

用户名

我是android的初学者,从列表视图打开文本文件时遇到了一些问题:

            package com.example.androidexplorer;

        import java.io.File;
        import java.util.ArrayList;
        import java.util.List;

        import android.net.Uri;
        import android.os.Bundle;
        import android.os.Environment;
        import android.app.AlertDialog;
        import android.app.ListActivity;
        import android.content.Intent;
        import android.view.View;
        import android.widget.ArrayAdapter;
        import android.widget.ListView;
        import android.widget.TextView;

        public class MainActivity extends ListActivity {

            private List<String> item = null;
            private List<String> path = null;
            private String root;
            private TextView myPath;

            SaveString saveStr = new SaveString();

            @Override
            public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
                myPath = (TextView)findViewById(R.id.path);

                root = Environment.getExternalStorageDirectory().getPath();

                getDir(root);
            }

            private void getDir(String dirPath)
            {
                myPath.setText("Location: " + dirPath);
                item = new ArrayList<String>();
                path = new ArrayList<String>();
                File f = new File(dirPath);
                File[] files = f.listFiles();

                if(!dirPath.equals(root))
                {
                    item.add(root);
                    path.add(root);
                    item.add("../");
                    path.add(f.getParent());    
                }

                for(int i=0; i < files.length; i++)
                {
                    File file = files[i];

                    if(!file.isHidden() && file.canRead()){
                        path.add(file.getPath());
                        if(file.isDirectory()){
                            item.add(file.getName() + "/");
                        }else{
                            item.add(file.getName());


                        }
                    }   

                    saveStr.savePathString = file.getName();
                }

                ArrayAdapter<String> fileList =
                        new ArrayAdapter<String>(this, R.layout.row, item);
                setListAdapter(fileList);   


            }

            @Override
            protected void onListItemClick(ListView l, View v, int position, long id) {
                // TODO Auto-generated method stub
                File file = new File(path.get(position));

                if (file.isDirectory())
                {
                    if(file.canRead()){
                        getDir(path.get(position));
                    }else{
                        new AlertDialog.Builder(this)
                            .setIcon(R.drawable.ic_launcher)
                            .setTitle("[" + file.getName() + "] folder can't be read!")
                            .setPositiveButton("OK", null).show();  
                    }   

                    saveStr.savePathString = file.getName();
                }else {

                    Intent intent1 = new Intent(MainActivity.this, ReadActivity.class);
                    startActivity(intent1);


                    /*new AlertDialog.Builder(this)
                            .setIcon(R.drawable.ic_launcher)
                            .setTitle("[" + file.getName() + "]")
                            .setPositiveButton("OK", null).show();*/


                  }
            }

        }

ReadActivity此类在textView上显示选定的文本文件

package com.example.androidexplorer;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;

public class ReadActivity extends Activity{

TextView textView;

SaveString saveStr = new SaveString();

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.read);

    //textView = (TextView)findViewById(R.id.textView1);

  File sdcard = Environment.getExternalStorageDirectory();

  //Get the text file
  File file = new File(sdcard, saveStr.savePathString);

  //Read text from file
  StringBuilder text = new StringBuilder();

  try {
      BufferedReader br = new BufferedReader(new FileReader(file));
      String line;

      while ((line = br.readLine()) != null) {
          text.append(line);
          text.append('\n');
      }
  }
  catch (IOException e) {
      //You'll need to add proper error handling here
  }

  //Find the view by its id
  TextView tv = (TextView)findViewById(R.id.textView1);   

  tv.setText(text);

}

}

当我在列表视图中单击文本文件时,我的程序停止了。我不明白为什么?

堆栈跟踪:

        01-07 10:40:21.250: I/Process(847): Sending signal. PID: 847 SIG: 9
    01-07 10:40:34.110: D/AbsListView(1481): Get MotionRecognitionManager
    01-07 10:40:34.200: D/libEGL(1481): loaded /system/lib/egl/libEGL_mali.so
    01-07 10:40:34.210: D/libEGL(1481): loaded /system/lib/egl/libGLESv1_CM_mali.so
    01-07 10:40:34.210: D/libEGL(1481): loaded /system/lib/egl/libGLESv2_mali.so
    01-07 10:40:34.230: D/OpenGLRenderer(1481): Enabling debug mode 0
    01-07 10:40:40.780: E/InputEventReceiver(1481): Exception dispatching input event.
    01-07 10:40:40.780: E/MessageQueue-JNI(1481): Exception in MessageQueue callback: handleReceiveCallback
    01-07 10:40:40.870: E/MessageQueue-JNI(1481): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.androidexplorer/com.example.androidexplorer.ReadActivity}; have you declared this activity in your AndroidManifest.xml?
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1556)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Instrumentation.execStartActivity(Instrumentation.java:1431)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Activity.startActivityForResult(Activity.java:3428)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Activity.startActivityForResult(Activity.java:3389)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Activity.startActivity(Activity.java:3599)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Activity.startActivity(Activity.java:3567)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.example.androidexplorer.MainActivity.onListItemClick(MainActivity.java:97)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.ListActivity$2.onItemClick(ListActivity.java:319)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.widget.AdapterView.performItemClick(AdapterView.java:301)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.widget.AbsListView.performItemClick(AbsListView.java:1287)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.widget.AbsListView$PerformClick.run(AbsListView.java:3078)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.widget.AbsListView.onTouchEvent(AbsListView.java:4174)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.View.dispatchTouchEvent(View.java:7379)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2462)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2195)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2177)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1482)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.Activity.dispatchTouchEvent(Activity.java:2469)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2125)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.View.dispatchPointerEvent(View.java:7564)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3543)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3475)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4585)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4563)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4667)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.os.MessageQueue.nativePollOnce(Native Method)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.os.MessageQueue.next(MessageQueue.java:125)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.os.Looper.loop(Looper.java:124)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at android.app.ActivityThread.main(ActivityThread.java:4944)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at java.lang.reflect.Method.invokeNative(Native Method)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at java.lang.reflect.Method.invoke(Method.java:511)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    01-07 10:40:40.870: E/MessageQueue-JNI(1481):   at dalvik.system.NativeStart.main(Native Method)
    01-07 10:40:40.880: D/AndroidRuntime(1481): Shutting down VM
    01-07 10:40:40.880: W/dalvikvm(1481): threadid=1: thread exiting with uncaught exception (group=0x40fe02b8)
    01-07 10:40:40.890: E/AndroidRuntime(1481): FATAL EXCEPTION: main
    01-07 10:40:40.890: E/AndroidRuntime(1481): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.androidexplorer/com.example.androidexplorer.ReadActivity}; have you declared this activity in your AndroidManifest.xml?
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1556)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1431)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Activity.startActivityForResult(Activity.java:3428)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Activity.startActivityForResult(Activity.java:3389)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Activity.startActivity(Activity.java:3599)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Activity.startActivity(Activity.java:3567)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.example.androidexplorer.MainActivity.onListItemClick(MainActivity.java:97)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.ListActivity$2.onItemClick(ListActivity.java:319)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.widget.AdapterView.performItemClick(AdapterView.java:301)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.widget.AbsListView.performItemClick(AbsListView.java:1287)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:3078)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.widget.AbsListView.onTouchEvent(AbsListView.java:4174)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.View.dispatchTouchEvent(View.java:7379)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2462)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2195)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2468)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2210)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2177)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1482)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.Activity.dispatchTouchEvent(Activity.java:2469)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2125)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.View.dispatchPointerEvent(View.java:7564)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3543)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3475)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4585)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4563)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4667)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.os.MessageQueue.nativePollOnce(Native Method)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.os.MessageQueue.next(MessageQueue.java:125)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.os.Looper.loop(Looper.java:124)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at android.app.ActivityThread.main(ActivityThread.java:4944)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at java.lang.reflect.Method.invokeNative(Native Method)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at java.lang.reflect.Method.invoke(Method.java:511)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    01-07 10:40:40.890: E/AndroidRuntime(1481):     at dalvik.system.NativeStart.main(Native Method)

最近的logcat错误:

        01-07 11:03:47.510: I/Process(2299): Sending signal. PID: 2299 SIG: 9
    01-07 11:04:12.710: D/AbsListView(2598): Get MotionRecognitionManager
    01-07 11:04:12.820: D/libEGL(2598): loaded /system/lib/egl/libEGL_mali.so
    01-07 11:04:12.830: D/libEGL(2598): loaded /system/lib/egl/libGLESv1_CM_mali.so
    01-07 11:04:12.830: D/libEGL(2598): loaded /system/lib/egl/libGLESv2_mali.so
    01-07 11:04:12.850: D/OpenGLRenderer(2598): Enabling debug mode 0
    01-07 11:04:16.080: D/AndroidRuntime(2598): Shutting down VM
    01-07 11:04:16.080: W/dalvikvm(2598): threadid=1: thread exiting with uncaught exception (group=0x40fe02b8)
    01-07 11:04:16.150: E/AndroidRuntime(2598): FATAL EXCEPTION: main
    01-07 11:04:16.150: E/AndroidRuntime(2598): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.androidexplorer/com.example.androidexplorer.ReadActivity}: java.lang.NullPointerException
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2146)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread.access$700(ActivityThread.java:140)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1238)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.os.Handler.dispatchMessage(Handler.java:99)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.os.Looper.loop(Looper.java:137)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread.main(ActivityThread.java:4944)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at java.lang.reflect.Method.invokeNative(Native Method)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at java.lang.reflect.Method.invoke(Method.java:511)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at dalvik.system.NativeStart.main(Native Method)
    01-07 11:04:16.150: E/AndroidRuntime(2598): Caused by: java.lang.NullPointerException
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at java.io.File.<init>(File.java:150)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at java.io.File.<init>(File.java:124)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at com.example.androidexplorer.ReadActivity.onCreate(ReadActivity.java:29)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.Activity.performCreate(Activity.java:5188)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2085)
    01-07 11:04:16.150: E/AndroidRuntime(2598):     ... 11 more

新的logcat错误:

        01-07 11:27:01.680: D/AbsListView(3072): Get MotionRecognitionManager
    01-07 11:27:01.920: D/libEGL(3072): loaded /system/lib/egl/libEGL_mali.so
    01-07 11:27:01.960: D/libEGL(3072): loaded /system/lib/egl/libGLESv1_CM_mali.so
    01-07 11:27:01.970: D/libEGL(3072): loaded /system/lib/egl/libGLESv2_mali.so
    01-07 11:27:02.020: D/OpenGLRenderer(3072): Enabling debug mode 0
    01-07 11:27:10.540: D/AbsListView(3286): Get MotionRecognitionManager
    01-07 11:27:10.770: D/libEGL(3286): loaded /system/lib/egl/libEGL_mali.so
    01-07 11:27:10.770: D/libEGL(3286): loaded /system/lib/egl/libGLESv1_CM_mali.so
    01-07 11:27:10.780: D/libEGL(3286): loaded /system/lib/egl/libGLESv2_mali.so
    01-07 11:27:10.800: D/OpenGLRenderer(3286): Enabling debug mode 0
    01-07 11:27:21.700: D/AndroidRuntime(3286): Shutting down VM
    01-07 11:27:21.700: W/dalvikvm(3286): threadid=1: thread exiting with uncaught exception (group=0x40fe02b8)
    01-07 11:27:21.710: E/AndroidRuntime(3286): FATAL EXCEPTION: main
    01-07 11:27:21.710: E/AndroidRuntime(3286): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.androidexplorer/com.example.androidexplorer.ReadActivity}: java.lang.NullPointerException
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2146)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread.access$700(ActivityThread.java:140)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1238)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.os.Handler.dispatchMessage(Handler.java:99)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.os.Looper.loop(Looper.java:137)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread.main(ActivityThread.java:4944)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at java.lang.reflect.Method.invokeNative(Native Method)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at java.lang.reflect.Method.invoke(Method.java:511)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at dalvik.system.NativeStart.main(Native Method)
    01-07 11:27:21.710: E/AndroidRuntime(3286): Caused by: java.lang.NullPointerException
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at java.io.File.<init>(File.java:150)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at java.io.File.<init>(File.java:124)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at com.example.androidexplorer.ReadActivity.onCreate(ReadActivity.java:32)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.Activity.performCreate(Activity.java:5188)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2085)
    01-07 11:27:21.710: E/AndroidRuntime(3286):     ... 11 more
    01-07 11:27:28.870: I/Process(3286): Sending signal. PID: 3286 SIG: 9
    01-07 11:29:07.870: D/AbsListView(3485): Get MotionRecognitionManager
    01-07 11:29:08.060: D/libEGL(3485): loaded /system/lib/egl/libEGL_mali.so
    01-07 11:29:08.060: D/libEGL(3485): loaded /system/lib/egl/libGLESv1_CM_mali.so
    01-07 11:29:08.080: D/libEGL(3485): loaded /system/lib/egl/libGLESv2_mali.so
    01-07 11:29:08.130: D/OpenGLRenderer(3485): Enabling debug mode 0
    01-07 11:29:13.360: D/AndroidRuntime(3485): Shutting down VM
    01-07 11:29:13.360: W/dalvikvm(3485): threadid=1: thread exiting with uncaught exception (group=0x40fe02b8)
    01-07 11:29:13.370: E/AndroidRuntime(3485): FATAL EXCEPTION: main
    01-07 11:29:13.370: E/AndroidRuntime(3485): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.androidexplorer/com.example.androidexplorer.ReadActivity}: java.lang.NullPointerException
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2146)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread.access$700(ActivityThread.java:140)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1238)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.os.Handler.dispatchMessage(Handler.java:99)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.os.Looper.loop(Looper.java:137)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread.main(ActivityThread.java:4944)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at java.lang.reflect.Method.invokeNative(Native Method)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at java.lang.reflect.Method.invoke(Method.java:511)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at dalvik.system.NativeStart.main(Native Method)
    01-07 11:29:13.370: E/AndroidRuntime(3485): Caused by: java.lang.NullPointerException
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at java.io.File.<init>(File.java:150)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at java.io.File.<init>(File.java:124)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at com.example.androidexplorer.ReadActivity.onCreate(ReadActivity.java:33)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.Activity.performCreate(Activity.java:5188)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2085)
    01-07 11:29:13.370: E/AndroidRuntime(3485):     ... 11 more
乔克斯·特雷克斯

您是否尝试读取错误?:

android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.androidexplorer/com.example.androidexplorer.ReadActivity}; have you declared this activity in your AndroidManifest.xml?

这可能意味着您没有在AndroidManifest中定义您的活动。正确定义它,您应该摆脱该错误。

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