Đen màn hình xuất hiện kể từ khi bạn không có quyền đăng camera trên android 7 thiết bị
Chuyển đến settings-> apps-> chọn của bạn cấp ứng dụng> permissions-> Bật phép camera và kiểm tra
bạn cũng có thể xử lý việc này bên trong mã của bạn
Add sau phép bạn manifest
<uses-permission android:name="android.permission.CAMERA" />
Để xin phép bạn có thể gọi như thế này.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
MY_PERMISSIONS_REQUEST_CAMERA);
Để kiểm tra quyền truy cập camera
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
}
Bây giờ gọi lại nếu người dùng đã thực hiện bất kỳ hành động.
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_CAMERA: {
Log.i("Camera", "G : " + grantResults[0]);
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// contacts-related task you need to do.
openCamera();
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
if (ActivityCompat.shouldShowRequestPermissionRationale
(this, Manifest.permission.CAMERA)) {
showAlert();
} else {
}
}
return;
}
// other 'case' lines to check for other
// permissions this app might request
}
}
Dưới đây là hoàn dụ
import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
public class MainActivity extends AppCompatActivity {
public static final int MY_PERMISSIONS_REQUEST_CAMERA = 100;
public static final String ALLOW_KEY = "ALLOWED";
public static final String CAMERA_PREF = "camera_pref";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
if (getFromPref(this, ALLOW_KEY)) {
showSettingsAlert();
} else if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.CAMERA)) {
showAlert();
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
MY_PERMISSIONS_REQUEST_CAMERA);
}
}
} else {
openCamera();
}
}
public static void saveToPreferences(Context context, String key,
Boolean allowed) {
SharedPreferences myPrefs = context.getSharedPreferences
(CAMERA_PREF, Context.MODE_PRIVATE);
SharedPreferences.Editor prefsEditor = myPrefs.edit();
prefsEditor.putBoolean(key, allowed);
prefsEditor.commit();
}
public static Boolean getFromPref(Context context, String key) {
SharedPreferences myPrefs = context.getSharedPreferences
(CAMERA_PREF, Context.MODE_PRIVATE);
return (myPrefs.getBoolean(key, false));
}
private void showAlert() {
AlertDialog alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle("Alert");
alertDialog.setMessage("App needs to access the Camera.");
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "DONT ALLOW",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
finish();
}
});
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "ALLOW",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA},
MY_PERMISSIONS_REQUEST_CAMERA);
}
});
alertDialog.show();
}
private void showSettingsAlert() {
AlertDialog alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle("Alert");
alertDialog.setMessage("App needs to access the Camera.");
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "DONT ALLOW",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
//finish();
}
});
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "SETTINGS",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
startInstalledAppDetailsActivity(MainActivity.this);
}
});
alertDialog.show();
}
@Override
public void onRequestPermissionsResult
(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_CAMERA: {
for (int i = 0, len = permissions.length; i < len; i++) {
String permission = permissions[i];
if (grantResults[i] == PackageManager.PERMISSION_DENIED) {
boolean showRationale =
ActivityCompat.shouldShowRequestPermissionRationale
(this, permission);
if (showRationale) {
showAlert();
} else if (!showRationale) {
// user denied flagging NEVER ASK AGAIN
// you can either enable some fall back,
// disable features of your app
// or open another dialog explaining
// again the permission and directing to
// the app setting
saveToPreferences(MainActivity.this, ALLOW_KEY, true);
}
}
}
}
// other 'case' lines to check for other
// permissions this app might request
}
}
public static void startInstalledAppDetailsActivity(final Activity context) {
if (context == null) {
return;
}
final Intent i = new Intent();
i.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
i.addCategory(Intent.CATEGORY_DEFAULT);
i.setData(Uri.parse("package:" + context.getPackageName()));
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
i.addFlags(Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
context.startActivity(i);
}
private void openCamera() {
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
startActivity(intent);
}
}
Không phải bạn có nghĩa vụ sử dụng Camera2 api cho phiên bản cao hơn Android? –