我在阅读手机存储空间时遇到问题。我必须列出手机中的所有音频文件，所以我试图通过＆＃34; activitycompact.requestPermissions＆＃34;来请求permisiion。唯一的问题是，当应用程序安装并首次打开时，它表示＆＃34; MusicPlayer已停止＆＃34;然后在该对话框之后打开Permissions请求，所以我允许它然后我不得不重新打开这个文件。我不知道在崩溃之前如何要求这些权限。
主要活动
public class MainActivity extends ListActivity {
private static final int UPDATE_FREQUENCY = 500;
private static final int STEP_VALUE = 4000;
private MediaCursorAdapter mediaAdapter = null;
private TextView selectedFile= null;
private SeekBar seekbar = null;
private MediaPlayer player = null;
private ImageButton playButton = null;
private ImageButton previousButton = null;
private ImageButton nextButton = null;
private boolean isStarted = true;
private String currentFile = "";
private boolean isMovingseekBar = false;
private final Handler handler = new Handler();
private final Runnable updatePositionRunnable = new Runnable() {
public void run() {
updatePosition();
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE},
1);
selectedFile = (TextView) findViewById(R.id.selectedfile);
seekbar = (SeekBar) findViewById(R.id.seekbar);
playButton = (ImageButton) findViewById(R.id.play);
previousButton = (ImageButton) findViewById(R.id.previous);
nextButton = (ImageButton) findViewById(R.id.next);
player = new MediaPlayer();
player.setOnCompletionListener(onCompletion);
player.setOnErrorListener(onError);
seekbar.setOnSeekBarChangeListener(seekBarChanged);
Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
if (null != cursor) {
cursor.moveToFirst();
mediaAdapter = new MediaCursorAdapter(this, R.layout.listitem, cursor);
setListAdapter(mediaAdapter);
playButton.setOnClickListener(onButtonClick);
nextButton.setOnClickListener(onButtonClick);
previousButton.setOnClickListener(onButtonClick);
}
}
@Override
protected void onListItemClick(ListView list, View view, int position,long id) {
super.onListItemClick(list, view, position, id);
currentFile = (String) view.getTag();
startPlay(currentFile);
}
@Override
protected void onDestroy(){
super.onDestroy();
handler.removeCallbacks(updatePositionRunnable);
player.stop();
player.reset();
player.release();
player = null;
}
private void startPlay(String file) {
selectedFile.setText(file);
seekbar.setProgress(0);
player.stop();
player.reset();
try {
player.setDataSource(file);
player.prepare();
player.start();
} catch (IllegalArgumentException e){
e.printStackTrace();
} catch (IllegalStateException e){
e.printStackTrace();
} catch (IOException e){
e.printStackTrace();
}
seekbar.setMax(player.getDuration());
playButton.setImageResource(android.R.drawable.ic_media_pause);
updatePosition();
isStarted = true;
}
private void stopPlay() {
player.stop();
player.reset();
playButton.setImageResource(android.R.drawable.ic_media_play);
handler.removeCallbacks(updatePositionRunnable);
seekbar.setProgress(0);
isStarted = false;
}
private void updatePosition() {
handler.removeCallbacks(updatePositionRunnable);
handler.postDelayed(updatePositionRunnable, UPDATE_FREQUENCY);
}
private class MediaCursorAdapter extends SimpleCursorAdapter{
MediaCursorAdapter(Context context, int layout, Cursor c){
super(context, layout,c,
new String[] {MediaStore.MediaColumns.DISPLAY_NAME, MediaStore.MediaColumns.TITLE, MediaStore.Audio.AudioColumns.DURATION},
new int[] {R.id.displayname, R.id.title,R.id.duration});
}
@Override
public void bindView(View view,Context context, Cursor cursor) {
TextView title = (TextView) view.findViewById(R.id.title);
TextView name = (TextView) view.findViewById(R.id.displayname);
TextView duration = (TextView) view.findViewById(R.id.duration);
name.setText(cursor.getString(
cursor.getColumnIndex(MediaStore.MediaColumns.DISPLAY_NAME)));
title.setText(cursor.getString(
cursor.getColumnIndex(MediaStore.MediaColumns.TITLE)));
view.setTag(cursor.getString(cursor.getColumnIndex(MediaStore.MediaColumns.DATA)));
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.listitem, parent, false);
bindView(v, context, cursor);
return v;
}
}
private View.OnClickListener onButtonClick = new View.OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.play: {
if (player.isPlaying()) {
handler.removeCallbacks(updatePositionRunnable);
player.pause();
playButton.setImageResource(android.R.drawable.ic_media_play);
} else {
if (isStarted) {
player.start();
playButton.setImageResource(android.R.drawable.ic_media_pause);
updatePosition();
} else {
startPlay(currentFile);
}
}
break;
}
case R.id.next: {
int seekto = player.getCurrentPosition() + STEP_VALUE;
if (seekto < player.getDuration())
seekto = player.getDuration();
player.pause();
player.seekTo(seekto);
player.start();
break;
}
case R.id.previous: {
int seekto = player.getCurrentPosition() - STEP_VALUE;
if (seekto < player.getDuration())
seekto = player.getDuration();
player.pause();
player.seekTo(seekto);
player.start();
break;
}
}
}
};
private MediaPlayer.OnCompletionListener onCompletion = new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
stopPlay();
}
};
private MediaPlayer.OnErrorListener onError = new MediaPlayer.OnErrorListener() {
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
return false;
}
};
private SeekBar.OnSeekBarChangeListener seekBarChanged = new SeekBar.OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
isMovingseekBar = false;
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fomUser) {
if (isMovingseekBar) {
player.seekTo(progress);
Log.i("OnSeekBarChangeListener", "onProgressChange");
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
isMovingseekBar = true;
}
};
答案 0 :(得分：0)
1）请确保您已在Manifest.XML中添加了权限
2）我看不到你正在处理所请求的许可结果。
从你的onCreate
中删除以下内容Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
if (null != cursor) {
cursor.moveToFirst();
mediaAdapter = new MediaCursorAdapter(this, R.layout.listitem, cursor);
setListAdapter(mediaAdapter);
}
并保持在
的一边 @Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
if(requestCode ==YOUR_REQ_CODE) {
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//Do your stuff here.
}
}
答案 1 :(得分：0)
看来问题是你没有等待获得许可。
首先，我将包含你需要代码的危险许可
if (ContextCompat.checkSelfPermission(thisActivity,
Manifest.permission.[Permissionname])
== PackageManager.PERMISSION_GRANTED) {
// Do Something here ...
}
else
{
//Ask for permission
}
等待权限活动结果，然后继续这样做。
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case PERMISSION_REQUEST_CODE: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// task you need to do.
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
}
return;
}
// other 'case' lines to check for other
// permissions this app might request.
}
}
请注意，只有在未获得许可的情况下才需要获得许可。
答案 2 :(得分：0)
试试这个，
在onCreate（）
if( checkIfAlreadyhavePermission(activity, Manifest.permission.READ_EXTERNAL_STORAGE) ){
// Add the code here the code you need to work after accepting permission
player = new MediaPlayer();
player.setOnCompletionListener(onCompletion);
player.setOnErrorListener(onError);
seekbar.setOnSeekBarChangeListener(seekBarChanged);
Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
if (null != cursor) {
cursor.moveToFirst();
mediaAdapter = new MediaCursorAdapter(this, R.layout.listitem, cursor);
setListAdapter(mediaAdapter);
}
}else {
requestForSpecificPermission(
activity, Manifest.permission.READ_EXTERNAL_STORAGE);
}
并将其添加到MainActivity
public boolean checkIfAlreadyhavePermission(Activity activity, String permission) {
int result = ContextCompat.checkSelfPermission(activity, permission);
if (result == PackageManager.PERMISSION_GRANTED) {
return true;
} else {
return false;
}
}
public void requestForSpecificPermission(Activity activity, String granted_permission) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
ActivityCompat.requestPermissions(activity, new String[]{granted_permission}, 101);
}
}
请注意如果您只有权限问题，那么它会起作用。请分享您的logcat
答案 3 :(得分：0)
当请求权限使用下面的代码..
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当你允许权限并调用你的特定方法时，代码下面会使用这个时间..
if (ActivityCompat.checkSelfPermission(EdittextActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(EdittextActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE)) {
WriteBtn(view); // hear define your code after getting permission.
}
else {
ActivityCompat.requestPermissions(EdittextActivity.this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
}
}
答案 4 :(得分：0)
这可以帮助您：
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<http://www.opengis.net/ont/geosparql#asWKT> "
<http://www.opengis.net/def/crs/EPSG/0/27572> MULTIPOLYGON (((729326 2521619,....