R cannot be resolved to a variable
Check your xml files in Eclipse Graphical Editor and fix problems.
Check project setup, right click on project, select properties, Java build path and
select correct Android version etc.
Right click on project, Android Tools, Fix Project Properties
Menu Eclipse select Project ->Clean.
Check project setup, right click on project, select properties, Java build path and
select correct Android version etc.
Right click on project, Android Tools, Fix Project Properties
Menu Eclipse select Project ->Clean.
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Další témata ....(Topics)
onSaveInstanceState, onRestoreInstanceState life cycle if screen orientation changed from log file.
Diagram of life cycle onSaveInstanceState, onRestoreInstanceState
[caption id="attachment_1169" align="alignleft" width="229" caption="Life cycle onRestoreInstanceState"][/caption]
// starts activity
15:27:12.801: INFO/onCreate(1828): onCreate()
15:27:12.811: INFO/onStart(1828): onStart()
15:27:12.821: INFO/onResume(1828): onResume()
// activity is running
15:27:33.651: DEBUG/dalvikvm(307): GC_EXPLICIT freed 186K, 53%
free 2770K/5831K, external 981K/1038K, paused 99ms
// change emulator state Ctrl+F11 landscape, portrait
15:27:40.427: INFO/ActivityManager(74): Config changed:
{ scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=2 layout=18 uiMode=17 seq=64}
// saved all variable values if need
15:27:40.581: INFO/onSaveInstanceState(1828): onSaveInstanceState()
15:27:40.602: INFO/onPause(1828): onPause()
15:27:40.612: INFO/onStop(1828): onStop()
15:27:40.631: INFO/onDestroy(1828): onDestroy()
// activity goes back to onCreate !!!!!!!!!
15:27:40.692: INFO/onCreate(1828): onCreate()
15:27:40.701: INFO/onStart(1828): onStart()
// restore all saved values of variables
15:27:40.711: INFO/onRestoreInstanceState(1828): onRestoreInstanceState()
// you can using saved values by onSaveInstanceState() in onResume
15:27:40.721: INFO/onResume(1828): onResume()
Diagram of life cycle onSaveInstanceState, onRestoreInstanceState
[caption id="attachment_1169" align="alignleft" width="229" caption="Life cycle onRestoreInstanceState"][/caption]
Put your sglite database to Android Eclipse project folder named Assets.
On device will copy database file to application folder as this example:
On device will copy database file to application folder as this example:
public void createDatabase(Context myContext) throws IOException {
String sPackName = myContext.getPackageName();
InputStream assetsDB = myContext.getAssets().open("myDatabase");
OutputStream dbOut = new FileOutputStream("/data/data/"+sPackName+"/database");
byte[] buffer = new byte[1024];
int length;
while ((length = assetsDB.read(buffer))>0){
dbOut.write(buffer, 0, length);
}
dbOut.flush();
dbOut.close();
assetsDB.close();
}
WakeLock, PowerManager,uses-permission Android sample.
Main.java
AndroidManifest.xml
Main.java
public class Main extends Activity {
private SensorManager mSensorManager;
private PowerManager mPowerManager;
private WindowManager mWindowManager;
private WakeLock mWakeLock;
private Button button;
private TextView textView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
// Get an instance of the SensorManager
mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
// Get an instance of the PowerManager
mPowerManager = (PowerManager) getSystemService(POWER_SERVICE);
// Get an instance of the WindowManager
mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
mWindowManager.getDefaultDisplay();
// Create a bright wake lock
mWakeLock = mPowerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, getClass()
.getName());
setContentView(R.layout.main);
textView = (TextView)findViewById(R.id.textView1);
button = (Button)findViewById(R.id.button1);
button.setOnClickListener(mButtonStopListener);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("onCreate", e.getMessage());
}
} // END onCreate
View.OnClickListener mButtonStopListener = new OnClickListener() {
public void onClick(View v) {
try {
mWakeLock.release();
textView.setText("mWakeLock.release()");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("onPause",e.getMessage());
}
}
};
@Override
protected void onResume() {
super.onResume();
/*
* when the activity is resumed, we acquire a wake-lock so that the
* screen stays on, since the user will likely not be fiddling with the
* screen or buttons.
*/
try {
mWakeLock.acquire();
textView.setText("mWakeLock.acquire()");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("onResume", e.getMessage());
}
}
@Override
protected void onPause() {
super.onPause();
// and release our wake-lock
try {
mWakeLock.release();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("onPause",e.getMessage());
}
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="//schemas.android.com/apk/res/android"
package="cz.okhelp.Main"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="7" />
<uses-permission android:name="android.permission.HARDWARE_TEST"></uses-permission>
<uses-permission android:name="android.permission.VIBRATE"></uses-permission>
<uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".ScreenBrightnessActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
// warning
private static String DB_PATH = "/data/data/cz.okhelp.german_czech_phrases/databases/";
// OK
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
// OK
DB_PATH = context.getFilesDir().getParentFile().getPath()
+ "/databases/";
}
Editace: 2014-02-15 20:14:31
Počet článků v kategorii: 396
Url:r-cannot-be-resolved-to-a-variable