我是android开发的新手,正在制作一个简单的计算器。一切正常,没有错误显示,但是每Buttons
按一次它们都无法正常工作。
我的目标SDK是,API 19: Android 4.4(Kitkat)
并使用进行编译API 20: Android 4.4(KitKat Wear)
。这是我的代码,
MainActivity.java
package edu.shihank.mycalcv2;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
public TextView tv;
public float numbBf;
public String Operation;
public ButtonClickListener btnClick;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView)findViewById(R.id.tv);
int idList[] = {R.id.zero, R.id.one, R.id.two, R.id.three, R.id.four,
R.id.five, R.id.six, R.id.seven, R.id.eight, R.id.nine, R.id.add,
R.id.sub, R.id.div, R.id.multi, R.id.equal, R.id.clear, R.id.history};
for(int id:idList){
View v = (View)findViewById(id);
v.setOnClickListener(btnClick);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void getKeyboard(String str) {
String tvNow = tv.getText().toString();
tvNow += str;
tv.setText(tvNow);
}
public void theResult() {
float numbAf = Float.parseFloat(tv.getText().toString());
float result = 0;
if(Operation.equals("+")){
result = numbAf + numbBf;
}
if(Operation.equals("-")){
result = numbAf - numbBf;
}
if(Operation.equals("*")){
result = numbAf * numbBf;
}
if(Operation.equals("/")){
result = numbAf / numbBf;
}
tv.setText(String.valueOf(result));
}
public void theMath(String str) {
numbBf = Float.parseFloat(tv.getText().toString());
Operation = str;
tv.setText("0");
}
private class ButtonClickListener implements OnClickListener{
@Override
public void onClick(View v) {
switch(v.getId()){
case R.id.clear:
tv.setText("0");
numbBf = 0;
Operation = "";
break;
case R.id.add:
theMath("+");
break;
case R.id.sub:
theMath("-");
break;
case R.id.div:
theMath("/");
break;
case R.id.multi:
theMath("*");
break;
case R.id.equal:
theResult();
break;
default:
String numb = ((Button) v).getText().toString();
getKeyboard(numb);
break;
}
}
}
}
谁能看到我做错了吗?
btnClick尚未初始化!试试这个:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView)findViewById(R.id.tv);
int idList[] = {R.id.zero, R.id.one, R.id.two, R.id.three, R.id.four,
R.id.five, R.id.six, R.id.seven, R.id.eight, R.id.nine, R.id.add,
R.id.sub, R.id.div, R.id.multi, R.id.equal, R.id.clear, R.id.history};
btnClick = new ButtonClickListener(); // add this line
for(int id:idList){
View v = (View)findViewById(id);
v.setOnClickListener(btnClick);
}
}
本文收集自互联网,转载请注明来源。
如有侵权,请联系 [email protected] 删除。
我来说两句