Android 学习笔记（8）——AlertDialog

public class MainActivity extends Activity implements View.OnClickListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.aty_alterdialog);
        Button button = (Button)findViewById(R.id.cancel);
        button.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.cancel:
                AlertDialog.Builder dialog = new AlertDialog.Builder(this); //step 1
                dialog.setTitle("系统提示");  // step 2
                dialog.setMessage("确定要退出吗");  // step 3
                dialog.setCancelable(false);
                dialog.setPositiveButton("确定", new DialogInterface.OnClickListener() { // step 4
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this, "你选择了确定", Toast.LENGTH_SHORT).show();
                        finish();
                    }
                }).create();   // step 5  这里creat（） 用不用都可以，默认是用上的。
                dialog.setNeutralButton("中立", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"你选择了中立",Toast.LENGTH_SHORT).show();
                    }
                });
                dialog.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this, "你选择了取消", Toast.LENGTH_SHORT).show();
                    }
                });
                dialog.show();
                break;
        }
    }
}