Solicitar permisos Android

[andresking95]

Hola a todos, estoy creando una aplicación para Android, pero la verdad es que soy muy novato y me esta dando muchos errores... Cree un reproductor mp3, pero al momento de iniciar la aplicación se detiene la aplicación y me sale el mensaje en pantalla. Llegue a la conclusión que debe ser un problema de permisos al leer la tarjeta sd, pero el tema es que no se como solicitarlos de manera adecuada. Paso a dejar mis actividades, clases y el manifest, ignorando los layout. Si alguien es tan amable de ayudarme se los agradecería muchísimo.

MainActivity.java :

package com.app1.appm;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;

import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity implements OnCompletionListener {

public MediaPlayer mp;
public ImageView play;
public ImageView next;
public ImageView plus;
public Handler mHandler = new Handler();;
public SongsManager songManager;
public ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
public int currentSongIndex = 0;

override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

// All player buttons
final ImageView play = (ImageView) findViewById(R.id.play);
final ImageView next = (ImageView) findViewById(R.id.next);
final ImageView plus = (ImageView) findViewById(R.id.plus);

// Mediaplayer
final MediaPlayer mp = new MediaPlayer();
SongsManager songManager = new SongsManager();

// Getting all songs list

songsList = songManager.getPlayList();

// By default play first song
playSong(0);

/**
* Play button click event
* plays a song and changes button to pause image
* pauses a song and changes button to play image
* */
play.setOnClickListener(new View.OnClickListener() {

override
public void onClick(View arg0) {
// check for already playing
if(mp.isPlaying()){
mp.pause();
// Changing button image to play button
play.setImageResource(R.drawable.play);
}else{
mp.start();
// Changing button image to pause button
play.setImageResource(R.drawable.pause);
}

}
});


/**
* Next button click event
* Plays next song by taking currentSongIndex + 1
* */
next.setOnClickListener(new View.OnClickListener() {

override
public void onClick(View arg0) {
// check if next song is there or not
if(currentSongIndex < (songsList.size() - 1)){
playSong(currentSongIndex + 1);
currentSongIndex = currentSongIndex + 1;
}else{
// play first song
playSong(0);
currentSongIndex = 0;
}

}
});



/**
* Button Click event for Play list click event
* Launches list activity which displays list of songs
* */
plus.setOnClickListener(new View.OnClickListener() {

override
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), PlayListActivity.class);
startActivityForResult(i, 100);
}
});

}

//Permisos

//

/**
* Receiving song index from playlist view
* and play the song
* */
override
protected void onActivityResult(int requestCode,
int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == 100){
currentSongIndex = data.getExtras().getInt("songIndex");
// play selected song
playSong(currentSongIndex);
}

}

/**
* Function to play a song
* param songIndex - index of song
* */
public void playSong(int songIndex) {
// Play song
try {
mp.reset();
mp.setDataSource(songsList.get(songIndex).get("songPath"));
mp.prepare();
mp.start();

// Changing Button Image to pause image
play.setImageResource(R.drawable.pause);

} catch (IOException e) {
e.printStackTrace();
}
}

override
public void onCompletion(MediaPlayer arg0) {
if(currentSongIndex < (songsList.size() - 1)){
playSong(currentSongIndex + 1);
currentSongIndex = currentSongIndex + 1;
}else{
// play first song
playSong(0);
currentSongIndex = 0;
}
}
override
public void onDestroy(){
super.onDestroy();
mp.release();
}

}


PlayListActivity.java :

package com.app1.appm;

import java.util.ArrayList;
import java.util.HashMap;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class PlayListActivity extends ListActivity {
// Songs list
public ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();

override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.playlist);

ArrayList<HashMap<String, String>> songsListData = new ArrayList<HashMap<String, String>>();

SongsManager plm = new SongsManager();
// get all songs from sdcard
this.songsList = plm.getPlayList();

// looping through playlist
for (int i = 0; i < songsList.size(); i++) {
// creating new HashMap
HashMap<String, String> song = songsList.get(i);

// adding HashList to ArrayList
songsListData.add(song);
}

// Adding menuItems to ListView
ListAdapter adapter = new SimpleAdapter(this, songsListData,
R.layout.playlist_item, new String[] { "songTitle" }, new int[] {
R.id.songTitle });

setListAdapter(adapter);

// selecting single ListView item
ListView lv = getListView();
// listening to single listitem click
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(getApplicationContext(),
MainActivity.class);
// Sending songIndex to PlayerActivity
in.putExtra("songIndex", songIndex);
setResult(100, in);
// Closing PlayListView
finish();
}
});
}
}


SongsManager.java (Supongo que aquí está el problema):
package com.app1.appm;

import android.os.Environment;

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.HashMap;

public class SongsManager {
// SDCard Path
final String MEDIA_PATH = Environment.getExternalStorageDirectory().getPath( ) + "/";
private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();

// Constructor
public SongsManager(){

}

/**
* Function to read all mp3 files from sdcard
* and store the details in ArrayList
* */
public ArrayList<HashMap<String, String>> getPlayList(){
File home = new File(MEDIA_PATH);

if (home.listFiles(new FileExtensionFilter()).length > 0) {
for (File file : home.listFiles(new FileExtensionFilter())) {
HashMap<String, String> song = new HashMap<String, String>();
song.put("songTitle", file.getName().substring(0, (file.getName().length() - 4)));
song.put("songPath", file.getPath());

// Adding each song to SongList
songsList.add(song);
}
}
// return songs list array
return songsList;
}

/**
* Class to filter files which are having .mp3 extension
* */
class FileExtensionFilter implements FilenameFilter {
public boolean accept(File dir, String name) {
return (name.endsWith(".mp3") || name.endsWith(".MP3"));
}
}
}

Utilities.java :

package com.app1.appm;

public class Utilities {

/**
* Function to convert milliseconds time to
* Timer Format
* Hours:Minutes:Seconds
* */
public String milliSecondsToTimer(long milliseconds){
String finalTimerString = "";
String secondsString = "";

// Convert total duration into time
int hours = (int)( milliseconds / (1000*60*60));
int minutes = (int)(milliseconds % (1000*60*60)) / (1000*60);
int seconds = (int) ((milliseconds % (1000*60*60)) % (1000*60) / 1000);
// Add hours if there
if(hours > 0){
finalTimerString = hours + ":";
}

// Prepending 0 to seconds if it is one digit
if(seconds < 10){
secondsString = "0" + seconds;
}else{
secondsString = "" + seconds;}

finalTimerString = finalTimerString + minutes + ":" + secondsString;

// return timer string
return finalTimerString;
}

/**
* Function to get Progress percentage
* param currentDuration
* param totalDuration
* */
public int getProgressPercentage(long currentDuration, long totalDuration){
Double percentage = (double) 0;

long currentSeconds = (int) (currentDuration / 1000);
long totalSeconds = (int) (totalDuration / 1000);

// calculating percentage
percentage =(((double)currentSeconds)/totalSeconds)*100;

// return percentage
return percentage.intValue();
}

/**
* Function to change progress to timer
* param progress -
* param totalDuration
* returns current duration in milliseconds
* */
public int progressToTimer(int progress, int totalDuration) {
int currentDuration = 0;
totalDuration = (int) (totalDuration / 1000);
currentDuration = (int) ((((double)progress) / 100) * totalDuration);

// return current duration in milliseconds
return currentDuration * 1000;
}
}

[mocelet]

Tienes que aprender antes de nada a mirar las excepciones en la pestaña Android Monitor. Cuando la app se cierra es por una Exception, y suele venir bastante bien explicado qué tipo de excepción, cuál es el mensaje de error, qué línea del código la produce y la secuencia de llamadas a métodos que derivó a ese punto.

Sin mirar en los logs qué línea es la que ha producido el error lo demás es perder el tiempo con elucubraciones y dar palos de ciego. Normalmente aparecerá el nombre de paquete de tu app por ahí entre la ristra de información que sale en el monitor.

Cuando lo tengas, pon el error por aquí y alguien te podrá ayudar, pero sin saber qué error te da poca ayuda puede darse :)