这是List View中Android Developers中给出的示例代码。我试图从一个主要活动发起这个。但它似乎有一些问题，因为当我点击主要活动中的按钮时它会崩溃。
package com.hsenidmobile.romeosierra.robotiumex;
import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.widget.SimpleCursorAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.ProgressBar;
public class ContactListActivity extends ListActivity
implements LoaderManager.LoaderCallbacks<Cursor> {
// This is the Adapter being used to display the list's data
SimpleCursorAdapter mAdapter;
// These are the Contacts rows that we will retrieve
static final String[] PROJECTION = new String[] {ContactsContract.Data._ID,
ContactsContract.Data.DISPLAY_NAME};
// This is the select criteria
static final String SELECTION = "((" +
ContactsContract.Data.DISPLAY_NAME + " NOTNULL) AND (" +
ContactsContract.Data.DISPLAY_NAME + " != '' ))";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a progress bar to display while the list loads
ProgressBar progressBar = new ProgressBar(this);
//progressBar.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, Gravity.CENTER));
progressBar.setIndeterminate(true);
getListView().setEmptyView(progressBar);
// Must add the progress bar to the root of the layout
ViewGroup root = (ViewGroup) findViewById(android.R.id.content);
root.addView(progressBar);
// For the cursor adapter, specify which columns go into which views
String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME};
int[] toViews = {android.R.id.text1}; // The TextView in simple_list_item_1
// Create an empty adapter we will use to display the loaded data.
// We pass null for the cursor, then update it in onLoadFinished()
mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, null, fromColumns, toViews, 0);
setListAdapter(mAdapter);
// Prepare the loader. Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);
}
// Called when a new Loader needs to be created
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// Now create and return a CursorLoader that will take care of
// creating a Cursor for the data being displayed.
CursorLoader cursorLoader = null;
return new CursorLoader(this, ContactsContract.Data.CONTENT_URI, PROJECTION, SELECTION, null, null);
}
// Called when a previously created loader has finished loading
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
mAdapter.swapCursor(data);
}
// Called when a previously created loader is reset, making the data unavailable
@Override
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
mAdapter.swapCursor(null);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Do something when a list item is clicked
}
}
任何不介意看这个并告诉我问题是什么的人？
编辑:: Logcat
05-19 16:28:56.990 2467 2487 W PlatformStatsUtil: Could not retrieve Usage & Diagnostics setting. Giving up.
05-19 16:28:57.041 1632 1827 I ActivityManager: START u0 {cmp=com.hsenidmobile.romeosierra.robotiumex/.ContactListActivity} from uid 10072 on display 0
05-19 16:28:57.041 1632 1703 W AudioTrack: AUDIO_OUTPUT_FLAG_FAST denied by client; transfer 4, track 48000 Hz, output 44100 Hz
05-19 16:28:57.074 1632 2093 W ActivityManager: Permission Denial: opening provider com.android.providers.contacts.ContactsProvider2 from ProcessRecord{d1211dc 2416:com.hsenidmobile.romeosierra.robotiumex/u0a72} (pid=2416, uid=10072) requires android.permission.READ_CONTACTS or android.permission.WRITE_CONTACTS
05-19 16:28:57.074 2416 3107 E AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
05-19 16:28:57.074 2416 3107 E AndroidRuntime: Process: com.hsenidmobile.romeosierra.robotiumex, PID: 2416
05-19 16:28:57.074 2416 3107 E AndroidRuntime: java.lang.RuntimeException: An error occurred while executing doInBackground()
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.os.AsyncTask$3.done(AsyncTask.java:325)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.FutureTask.run(FutureTask.java:242)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.lang.Thread.run(Thread.java:761)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: Caused by: java.lang.SecurityException: Permission Denial: opening provider com.android.providers.contacts.ContactsProvider2 from ProcessRecord{d1211dc 2416:com.hsenidmobile.romeosierra.robotiumex/u0a72} (pid=2416, uid=10072) requires android.permission.READ_CONTACTS or android.permission.WRITE_CONTACTS
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.os.Parcel.readException(Parcel.java:1684)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.os.Parcel.readException(Parcel.java:1637)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.app.ActivityManagerProxy.getContentProvider(ActivityManagerNative.java:4199)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.app.ActivityThread.acquireProvider(ActivityThread.java:5476)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.app.ContextImpl$ApplicationContentResolver.acquireUnstableProvider(ContextImpl.java:2239)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.ContentResolver.acquireUnstableProvider(ContentResolver.java:1517)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.ContentResolver.query(ContentResolver.java:516)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.CursorLoader.loadInBackground(CursorLoader.java:64)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.CursorLoader.loadInBackground(CursorLoader.java:56)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.AsyncTaskLoader.onLoadInBackground(AsyncTaskLoader.java:312)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:69)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:66)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at android.os.AsyncTask$2.call(AsyncTask.java:305)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: at java.util.concurrent.FutureTask.run(FutureTask.java:237)
05-19 16:28:57.074 2416 3107 E AndroidRuntime: ... 3 more
05-19 16:28:57.075 1632 1827 W ActivityManager: Force finishing activity com.hsenidmobile.romeosierra.robotiumex/.ContactListActivity
05-19 16:28:57.076 1632 1827 W ActivityManager: Force finishing activity com.hsenidmobile.romeosierra.robotiumex/.MainActivity
由于logcat表示android.permission.READ_CONTACTS或android.permission.WRITE_CONTACTS存在权限问题。但我已在android清单中拥有必要的权限集。我仍然遇到了问题。
答案 0 :(得分：1)
你需要android.permission.READ_CONTACTS权限。
因此，在项目的清单中，您需要添加以下行
<uses-permission android:name="android.permission.READ_CONTACTS" />
此外，如果您的目标是Android 23及更高版本，那么您还需要获得运行时权限。
要获得用户的运行时权限，
在您的onCreate of activity
中添加此代码 int result= ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS);
if (result != PackageManager.PERMISSION_GRANTED) {
//we don't have permission to read contacts...so ask user to grant permission
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, 7);
}
else{
// we already got the permission from user...now read contacts
readContacts();
}
您有onRequestPermissionsResult方法来捕获此事件
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 7) {
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
readContacts();
} else {
Toast.makeText(this, "Can't read contacts as you have declined the permission.", Toast.LENGTH_SHORT).show();
}
}
}
最后你的代码来阅读联系人
//This is your method to read contacts
private void readContacts()
{
//your code here
}
答案 1 :(得分：0)
你好试试吧
获取清单中的权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
在运行时获取权限
if(askForPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE,WRITE_EXST)){
//Your code here if have permission
}
private boolean askForPermission(String permission, Integer requestCode) {
if (ContextCompat.checkSelfPermission(MainActivity.this, permission) != PackageManager.PERMISSION_GRANTED) {
//requesting for permission
ActivityCompat.requestPermissions(MainActivity.this, new String[]{permission}, requestCode);
return false;
} else {
Toast.makeText(this, "" + permission + " is already granted.", Toast.LENGTH_SHORT).show();
return true;
}
}