带有一个，两个和三个按钮的Android Alert对话框

127

苏拉奇：

我不会经常发出警报，但是每次我都会花一些时间阅读文档并弄清楚如何做。由于我现在必须做几次，因此我将在下面写下一个答案，以后我会再说回来。具体来说，我想比较基本代码

一键式（确定）
两个按钮（确定和取消）
三个按钮（正，负，其他）

最好将这三种常见警报类型的基本代码放在一个位置，以便将来方便参考和修改。这个问题问一个按钮怎么做。

苏拉奇：

一键式

import android.support.v7.app.AlertDialog;

public class MainActivity extends AppCompatActivity {

    public void showAlertDialogButtonClicked(View view) {

        // setup the alert builder
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("My title");
        builder.setMessage("This is my message.");

        // add a button
        builder.setPositiveButton("OK", null);

        // create and show the alert dialog
        AlertDialog dialog = builder.create();
        dialog.show();
    }
}

两个按钮

public class MainActivity extends AppCompatActivity {

    public void showAlertDialogButtonClicked(View view) {

        // setup the alert builder
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("AlertDialog");
        builder.setMessage("Would you like to continue learning how to use Android alerts?");

        // add the buttons
        builder.setPositiveButton("Continue", null);
        builder.setNegativeButton("Cancel", null);

        // create and show the alert dialog
        AlertDialog dialog = builder.create();
        dialog.show();
    }
}

三个按钮

public class MainActivity extends AppCompatActivity {

    public void showAlertDialogButtonClicked(View view) {

        // setup the alert builder
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Notice");
        builder.setMessage("Launching this missile will destroy the entire universe. Is this what you intended to do?");

        // add the buttons
        builder.setPositiveButton("Launch missile", null);
        builder.setNeutralButton("Remind me later", null);
        builder.setNegativeButton("Cancel", null);

        // create and show the alert dialog
        AlertDialog dialog = builder.create();
        dialog.show();
    }
}

If the button text it too long to all fit horizontally, then it will automatically get laid out in a vertical column of three buttons.

Handling Button Clicks

The OnClickListener was null in the above examples. You can replace null with a listener to do something when the user taps a button. For example:

builder.setPositiveButton("Launch missile", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {

        // do something like...
        launchMissile();
    }
});

Going On

There are many more varieties of dialogs that you can make. See the documentation for help with this.

Since only three buttons are supported in an AlertDialog, here is an example of a dialog with a list.

public class MainActivity extends AppCompatActivity {

    public void showAlertDialogButtonClicked(View view) {

        // setup the alert builder
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Choose an animal");

        // add a list
        String[] animals = {"horse", "cow", "camel", "sheep", "goat"};
        builder.setItems(animals, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                switch (which) {
                    case 0: // horse
                    case 1: // cow
                    case 2: // camel
                    case 3: // sheep
                    case 4: // goat
                }
            }
        });

        // create and show the alert dialog
        AlertDialog dialog = builder.create();
        dialog.show();
    }
}

See this answer for similar examples of a radio button list and a checkbox list.

Notes

Use string resources rather than hard coded strings.
您可以将所有内容包装在扩展的类中，DialogFragment以方便对话框的重用。（请参阅此以获得帮助。）
这些示例使用支持库来支持API 11之前的版本。因此，导入应为
```
import android.support.v7.app.AlertDialog;
```
onCreate为了简洁起见，我在上面的示例中省略了该方法。那里没有什么特别的。

也可以看看

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。

编辑于 2020-09-22

我来说两句

0 条评论

登录后参与评论

上一篇：创建项目ASP.NET Core（.NET Core）和ASP.NET Core（.NET Framework）有什么区别