Question

单击播放列表按钮时，将显示播放列表以选择歌曲

    btnPlaylist.setOnClickListener(new View.OnClickListener() {

                @SuppressWarnings("unchecked")
                @Override
                public void onClick(View arg0) {
                    Intent myIntent = new Intent(context,
                            AudioPlayListActivity.class);

                    Bundle bundle = new Bundle();
                    bundle.putParcelableArrayList("listfrommain",
                            (ArrayList<? extends Parcelable>) songsList);
                    myIntent.putExtras(bundle);

                    startActivityForResult(myIntent, 1);
                }
            });

当我在ListView上选择歌曲播放歌曲时

lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting listitem index
                int songIndex = position;

                // Starting new intent
                Intent in = new Intent(context, AudioPlayerMainActivity.class);

                in.putExtra("songIndex", songIndex);

                Bundle bundle = new Bundle();
                bundle.putParcelableArrayList("mylist",
                        (ArrayList<? extends Parcelable>) songsList);
                in.putExtras(bundle);

                // set result for Activity
                setResult(1, in);

                // Closing PlayListView
                finish();
            }

        });

收到ArrayList和songIndex

时出错

   `05-22 01:48:24.805: E/AndroidRuntime(5549): FATAL EXCEPTION: main
    05-22 01:48:24.805: E/AndroidRuntime(5549): Process: com.example.demotablayout, PID: 5549`enter code here`
    05-22 01:48:24.805: E/AndroidRuntime(5549): java.lang.RuntimeException: Failure delivering result ResultInfo{who=Audio Player, request=1, result=1, data=Intent { cmp=com.example.demotablayout/com.android.audioplayer.AudioPlayerMainActivity (has extras) }} to activity {com.example.demotablayout/com.android.main.MainActivity}: java.lang.NullPointerException
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3351)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:3394)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread.access$1300(ActivityThread.java:135)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.os.Handler.dispatchMessage(Handler.java:102)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.os.Looper.loop(Looper.java:136)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread.main(ActivityThread.java:5001)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at java.lang.reflect.Method.invokeNative(Native Method)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at java.lang.reflect.Method.invoke(Method.java:515)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at dalvik.system.NativeStart.main(Native Method)
    05-22 01:48:24.805: E/AndroidRuntime(5549): Caused by: java.lang.NullPointerException
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at com.android.audioplayer.AudioPlayerMainActivity.onActivityResult(AudioPlayerMainActivity.java:87)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityGroup.dispatchActivityResult(ActivityGroup.java:122)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3347)
    05-22 01:48:24.805: E/AndroidRuntime(5549):     ... 11 more
    `

Answer 1

这是onActivityResult代码

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == 1) {
            try {
                Bundle b = data.getExtras();
                songsList = (ArrayList<HashMap<String, String>>) b
                        .getSerializable("mylist");
                musicSrv.setList(songsList);
                currentSongIndex = data.getExtras().getInt("songIndex");
                Log.d(VIEW_LOG_TAG, currentSongIndex + "");
                // play selected song
                musicSrv.setSong(currentSongIndex);
                currentSongIndex = data.getExtras().getInt("songIndex");
                Log.d(VIEW_LOG_TAG, currentSongIndex + "");
                // play selected song
                musicSrv.setSong(currentSongIndex);
                Log.d("INDEX", currentSongIndex + "");
                musicSrv.playSong();
            } catch (Exception e) {
                e.printStackTrace();
            }
            // setting button Play
            btnPlay.setImageResource(R.drawable.img_btn_pause);
            // setting title for the player
            songTitleLabel.setText(songsList.get(currentSongIndex).get(
                    "songTitle"));
        }
    }

如何修复错误：无法提供结果ResultInfo

1 个答案: