Question

我正在尝试制作一个演示Android MediaPlayer使用的简单应用。应用程序布局显示“选择”按钮，TextView和“播放”按钮。用户单击选择按钮，TextView（到目前为止成功）显示URI，播放按钮应启动MediaPlayer。但我不知道如何让onActivityResult（）在任何地方发送路径。

public class MainActivity extends Activity {

private static final int MUSIC_ID = 1;
Intent intent;
Button chooseButton;
Button playButton;
TextView pathText;
MediaPlayer mp;
Sound sound;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // set our buttons in the layout
    chooseButton = (Button) findViewById(R.id.choose);
    playButton = (Button) findViewById(R.id.play);

    // and an TextView that will display the path
    pathText = (TextView) findViewById(R.id.pathText);

    // setOnClickListeners to the buttons
    chooseButton.setOnClickListener(chooseButtonListener);
    playButton.setOnClickListener(playButtonListener);


} // end onCreate


private OnClickListener chooseButtonListener = new OnClickListener(){

    // When chooseButton is clicked, make an Intent that will get
    // the path of the file and run startActivityForResult method

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("audio/*");
        startActivityForResult(intent, MUSIC_ID);

    }

};


protected final void onActivityResult(int requestCode, int resultCode, Intent data) {

    // if everything went well, get the URI path from the intent.
    if(resultCode == RESULT_OK && requestCode == MUSIC_ID){
        Uri uri = data.getData();

        // try to set the TextView to path (this works) and convert the URI
        try{
            pathText.setText(uri.toString()); // Here the path displays fine
            Sound sound = new Sound(); // Make a Sound object
            sound.setPath(uri.toString()); // set the path of the object
        }
        catch(Exception e){
            Toast toast = Toast.makeText(getApplicationContext(), "Null!", Toast.LENGTH_SHORT);
            toast.show();
        }
    }
}


private OnClickListener playButtonListener = new OnClickListener(){

    // When the playButton is clicked, try to create a
    // MediaPlayer that will use the path of the Sound Object
    // or otherwise display a toast.
    @Override
    public void onClick(View v) {

        try {
            mp.setDataSource(sound.getPath()); // get the path of the object
            mp.prepare();
            mp.setLooping(true);
            mp.start(); 
        }
        catch (Exception e){
            Toast toast = Toast.makeText(getApplicationContext(), "Null!", Toast.LENGTH_SHORT);
            toast.show();
        }


    }   
};

} // end MainActivity

这是Sound构造函数：

public class Sound {


public String path;

// constructor
public Sound () {

    path = null;
}

public void setPath(String filePath) {
    path = filePath;
}

public String getPath() {
    return path;
}

}

我不知道如何在不启动onActivityResult内部的MediaPlayer的情况下将onActivityResult的路径发送到playButtonListener。有一个简单的解决方案，我只是不知道吗？

Answer 1

您在onActivityResult中创建的Sound对象是一个局部变量，它会覆盖您的全局变量。从

更改以下行

       pathText.setText(uri.toString()); // Here the path displays fine
       Sound sound = new Sound(); // Make a Sound object
       sound.setPath(uri.toString()); // set the path of the object

到

       pathText.setText(uri.toString()); // Here the path displays fine
       sound = new Sound(); // Make a Sound object
       sound.setPath(uri.toString()); // set the path of the object

另一个选择是甚至不打扰创建声音对象，因为你的playButtonListener应该访问文本视图并在那里获取URL。这两种方法都应该足够好。

祝你好运

从onActivityResult（）发送字符串到对象

1 个答案: