android 情景模式来电铃声分析（二）

http://blog.csdn.net/jkkjklmn/article/details/6959686

DefaultRingtonePreference单击后出现的是一个AlertDialog，但是在DefaultRingtonePreference没看见任何构造Dialog的信息，显然构建在父类RingtonePreference中，

在RingtonePreference.java中：

protected void onClick() { //注意这对DefaultRingtonePreference单机事件左的处理有跳转
        // Launch the ringtone picker
        Intent intent = new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
        onPrepareRingtonePickerIntent(intent);
        getPreferenceManager().getActivity().startActivityForResult(intent, mRequestCode);
}

这里的startActivityForResult就跳转到了RingtonePickerActivity.java文件里面，

在RingtonePickerActivity.java中：

public void onClick(DialogInterface dialog, int which) {
Log.i(TAG,"------onClick----");
boolean positiveResult = which == DialogInterface.BUTTON_POSITIVE;

// Stop playing the previous ringtone
mRingtoneManager.stopPreviousRingtone();

if (positiveResult) {
    Intent resultIntent = new Intent();
    Uri uri = null;

    if (mClickedPos == mDefaultRingtonePos) {
        // Set it to the default Uri that they originally gave us
        uri = mUriForDefaultItem;
    } else if (mClickedPos == mSilentPos) {
        // A null Uri is for the 'Silent' item
        uri = null;
    } else {
        uri = mRingtoneManager.getRingtoneUri(getRingtoneManagerPosition(mClickedPos));
    }

    resultIntent.putExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI, uri);
    setResult(RESULT_OK, resultIntent);
} else {
    setResult(RESULT_CANCELED);
}

会把当前选中的那个铃声的URI返回给在RingtonePreference.java，