Okhelp.cz

Recepty, články, nápady, programování. Dříve dum-zahrada, finance, internet a know-how.okhelp.cz Pro lepší výsledky hledání používejte i diakritiku.

Android startup tutorial for developers video


AD MOB


397LW NO topic_id




AD

Další témata ....(Topics)


296

On orientation changed view button textview not visible Android | on-orientation-changed-view-button-textview-not-visible-android


Try add to AndroidManifest.xml configChanges for your Activity
android:configChanges="keyboardHidden|orientation|screenSize"


 <activity android:name=".MainActivity"
                  android:label="@string/app_name"
                  android:configChanges="keyboardHidden|orientation|screenSize"
                  >
25

Copy sqlite database from apk package to device folder Android example | copy-sqlite-database-from-apk-to-device-folder-android-example


Put your sglite database to Android Eclipse project folder named Assets.
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();
}


148

Crop cropped cut bitmap image pictures Android example | crop-cropped-cut-bitmap-image-pictures-android-example


Cut, shear, clip, snip, crop a bitmap, picture, image Android example

public class ApokusActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}

		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();

			canvas.drawColor(Color.YELLOW);


			// you need to insert a image flower_blue into res/drawable folder
			paint.setFilterBitmap(true);
			Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);

			Bitmap croppedBmp = Bitmap.createBitmap(bitmapOrg, 0, 0,
					bitmapOrg.getWidth() / 2, bitmapOrg.getHeight());
			int h = bitmapOrg.getHeight();
			canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			canvas.drawBitmap(croppedBmp, 10, 10 + h + 10, paint);

		}

	}
}



crop bitmap android
297

Shared Preferences file path Android | shared-preferences-file-path-android



/data/data/<package>/shared_prefs/<package>_preferences.xml

String TAG = "MyActivityName";
File f = new File("/data/data/"+this.getPackageName()
+"/shared_prefs/"+this.getPackageName()+"_preferences.xml");
if(f.exists())
	Log.d(TAG, "exist");
else
	Log.d(TAG, "not exist");

204

java.lang.NullPointerException: println needs a message | java-lang-nullpointerexception-println-needs-a-message


Problemi is in e.getMessage() what can return null and Log.e (String tag, String msg) will throws an new exception !!!!
Problem and solution:

      	try {
      		int [] i = {1};
      		int z = i[5];
      	} catch (ArrayIndexOutOfBoundsException e) {
      		String s = e.toString(); // s == java.lang.ArrayIndexOutOfBoundsException
                // try to testing String s for null value
      		if(s != null)
      		 Log.e("bla", s);
      		else 
      		 Log.e("bla", "My error text 1");
      		
      		String s2 = e.getMessage(); // s2 == null !!!!!!!
                // you need to testing String s2 for null value , or you get FATAL EXCEPTION: main
                // and application will be crashed
       		String s2 = e.getMessage(); // s2 == null !!!!!!!
      		if(s2 != null)
      		 Log.e("bla2", e.getMessage());
      		else 
      		 Log.e("bla2", "My error text 2");
     		
                // this is OK
      		e.printStackTrace();
      	}


LogCat:

E/bla(855): java.lang.ArrayIndexOutOfBoundsException

 E/bla2(855): My error text 2

 W/System.err(855): java.lang.ArrayIndexOutOfBoundsException
 W/System.err(855): 	at cz.okhelp.motion._MotionActivity.onTouchEvent(_MotionActivity.java:54)
 W/System.err(855): 	at android.app.Activity.dispatchTouchEvent(Activity.java:2099)
 W/System.err(855): 	at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
 W/System.err(855): 	at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
 W/System.err(855): 	at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
 W/System.err(855): 	at android.os.Handler.dispatchMessage(Handler.java:99)
 W/System.err(855): 	at android.os.Looper.loop(Looper.java:123)
 W/System.err(855): 	at android.app.ActivityThread.main(ActivityThread.java:3683)
 W/System.err(855): 	at java.lang.reflect.Method.invokeNative(Native Method)
 W/System.err(855): 	at java.lang.reflect.Method.invoke(Method.java:507)
 W/System.err(855): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
 W/System.err(855): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
 W/System.err(855): 	at dalvik.system.NativeStart.main(Native Method)




Or you can using this code:

      	try {
      		int [] i = {1};
      		int z = i[5];
      	} catch (Exception e) {
      		
      		
      		StringBuilder sb = new  StringBuilder().append(e.getClass().getSimpleName()); 
          if  (e.getMessage() != null) { 
              sb.append("

"); sb.append(e.getMessage()); } Log.e("err", sb.toString()); // E/err(336): ArrayIndexOutOfBoundsException // this code write out all message Log.e("myError", "methodName", e); } // E/myError(371): methodName // E/myError(371): java.lang.ArrayIndexOutOfBoundsException // E/myError(371): at cz.okhelp.motion._MotionActivity.onTouchEvent(_MotionActivity.java:54) // E/myError(371): at android.app.Activity.dispatchTouchEvent(Activity.java:2099) // E/myError(371): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675) // E/myError(371): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194) // E/myError(371): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878) // E/myError(371): at android.os.Handler.dispatchMessage(Handler.java:99) // E/myError(371): at android.os.Looper.loop(Looper.java:123) // E/myError(371): at android.app.ActivityThread.main(ActivityThread.java:3683) // E/myError(371): at java.lang.reflect.Method.invokeNative(Native Method) // E/myError(371): at java.lang.reflect.Method.invoke(Method.java:507) // E/myError(371): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) // E/myError(371): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) // E/myError(371): at dalvik.system.NativeStart.main(Native Method)



Editace: 2014-02-15 20:48:27
Počet článků v kategorii: 397
Url:android-startup-tutorial-for-developers-video

AD
11 Share
Share
Tweet