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Start Activity from list - launches other activities from list


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Activities launcher

public class MainActivity extends ListActivity {
    private class Sample {
        private CharSequence title;
        private Class<? extends Activity> activityClass;

        public Sample(int titleResId, Class<? extends Activity> activityClass) {
            this.activityClass = activityClass;
            this.title = getResources().getString(titleResId);
        }

        @Override
        public String toString() {
            return title.toString();
        }
    }

    private static Sample[] mSamples;

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

        // Instantiate the list of samples.
        mSamples = new Sample[]{
                new Sample(R.string.title_first_app, FirstActivity.class),
                new Sample(R.string.title_second_app, SecondActivity.class),
                new Sample(R.string.title_third_app, ThirdActivity.class),
        };

        setListAdapter(new ArrayAdapter<Sample>(this,
                android.R.layout.simple_list_item_1,
                android.R.id.text1,
                mSamples));
    }

    @Override
    protected void onListItemClick(ListView listView, View view, int position, long id) {
        // Launch the sample associated with this list position.
        startActivity(new Intent(MainActivity.this, mSamples[position].activityClass));
    }
}


397LW NO topic_id




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Check your xml files in Eclipse Graphical Editor and fix problems.

r-cannot-be-resolved-android

Check project setup, right click on project, select properties, Java build path and
select correct Android version etc.
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Right click on project, Android Tools, Fix Project Properties

Menu Eclipse select Project ->Clean.
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Get Context Java Android example | get-context-java-android-example


getContext() getApplicationContext() method Java Android example source






Context myContext_1 = ThisClassName.this; // to open a Dialog
Context myContext_2 = getContext();
Context myContext_3 = this.getContext();
Context myContext_4 = this;
Context myContext_5 = this.getApplicationContext ();


OnClickListener getImageBtnOnClick = new OnClickListener() {
public void onClick(View view) {
Context context = view.getContext();

}
};
// Toast
Toast.makeText(getApplicationContext(), "Context == getApplicationContext "
, Toast.LENGTH_SHORT).show();



// store Context in public class
public class MyActivity extends Activity {
public static Context myCnt = null;
...
protected void onCreate(Bundle icicle) {
...
myCnt = this;
MyStorage.setContext(myCnt);
// or
// MyStorage.setContext(this);

// cntxFromStorage == this
Context cntxFromStorage = MyStorage.getContext();
...
};
};

public class MyStorage
{
private static Context cntStorageContext = null;


public static Context getContext() {
return cntStorageContext;
}

public static void setContext(Context context) {
MyStorage.cntStorageContext = context;
}


};

class DataBaseHelper extends SQLiteOpenHelper {
// get MyActivity context
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210

No Launcher activity found Android Emulator Error | no-launcher-activity-found-android-emulator-error


Error: No Launcher activity found!
The launch will only sync the application package on the device!
Android emulator not showing the app
Workaround:
Check AndroidManifest.xml for MAIN and LAUNCHER. MyActivity.java is first Activity what will opened if .apk is installed.

<application android:label="@string/app_name" android:icon="@drawable/icon">
    <activity android:name="MyActivity"
              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>
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Shuffle List ArrayList Collections Java example | shuffle-list-arraylist-collections-java-example


Add and shuffle elements in LinkedList or ArrayList Java basic example.


import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = {"nothing", "Hello", "people"
				, "bye-bye", "hello", "world!", "End" };
		   List<String> arrayList = new LinkedList<String>();
            for(String s: arrayOfString)
		     arrayList.add(s);

		    Collections.shuffle(arrayList);

		    System.out.println(arrayList);
		    
		  }
}
/*
[hello, world!, bye-bye, nothing, people, End, Hello]
*/


54

Timer simple TimerTask Java Android example | timer-simple-timertask-java-android-example


TimerTask with updating of TextView here




package cz.okhelp.timer;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class TimerActivity extends Activity {
TextView hTextView;
@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        hTextView = (TextView)findViewById(R.id.idTextView);
        MyTimerTask myTask = new MyTimerTask();
        Timer myTimer = new Timer();
//        public void schedule (TimerTask task, long delay, long period) 
//        Schedule a task for repeated fixed-delay execution after a specific delay.
//
//        Parameters
//        task  the task to schedule. 
//        delay  amount of time in milliseconds before first execution. 
//        period  amount of time in milliseconds between subsequent executions. 

        myTimer.schedule(myTask, 3000, 1500);        
        
    }
class MyTimerTask extends TimerTask {
	  public void run() {
		  // ERROR
		 hTextView.setText("Impossible");
		 // how update TextView in link below  
                 // //android.okhelp.cz/timer-task-timertask-run-cancel-android-example/
                 
	    System.out.println("");
	  }
	}


}


//android.okhelp.cz/asynctask-example-android-with-progressbar/
//android.okhelp.cz/timer-task-timertask-run-cancel-android-example/


Editace: 2016-02-25 19:32:45
Počet článků v kategorii: 397
Url:start-activity-from-list-launches-other-activities-from-list

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