Android startup tutorial for developers video
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How install Android emulator on PC
//developer.android.com/sdk/installing.html
Download links:
Java Development Kit JDK download
Eclipse download
Android SDK download
//developer.android.com/sdk/installing.html
Download links:
Java Development Kit JDK download
Eclipse download
Android SDK download
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Další témata ....(Topics)
Spinner in Android application is equivalent of ComboBox in WinApi.
Spinner get selected item to string example.
Spinner get selected item position to int example.
Main activity class MainComboBox.java
File MyOnItemSelectedListener.java
strings.xml
main.xml
Spinner get selected item to string example.
Spinner get selected item position to int example.
Main activity class MainComboBox.java
public class MainComboBox extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.countries_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new MyOnItemSelectedListener());
Button myButton =(Button)findViewById(R.id.button1);
myButton.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
Spinner sp = (Spinner)findViewById(R.id.spinner);
String spinnerString = null;
spinnerString = sp.getSelectedItem().toString();
int nPos = sp.getSelectedItemPosition();
Toast.makeText(getApplicationContext(), "getSelectedItem=" + spinnerString,
Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "getSelectedItemPosition=" + nPos,
Toast.LENGTH_LONG).show();
}
});
}
}
File MyOnItemSelectedListener.java
public class MyOnItemSelectedListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
Toast.makeText(parent.getContext(), "Item is " +
parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
}
public void onNothingSelected(AdapterView parent) {
// Do nothing.
}
}
strings.xml
<resources>
<string name="hello">Hello World, MainComboBox!</string>
<string name="app_name">ComboBox</string>
<string name="prompt">Choose a country</string>
<string-array name="countries_array">
<item>China</item>
<item>India</item>
<item>USA</item>
<item>Indonesia</item>
<item>Brazil</item>
<item>Pakistan</item>
<item>Nigeria</item>
<item>Bangladesh</item>
<item>Russia</item>
</string-array>
</resources>
main.xml
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
android:orientation="vertical"
android:padding="10dip"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:text="@string/prompt"
/>
<Spinner
android:id="@+id/spinner"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:prompt="@string/prompt"
/>
<Button android:text="Button" android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
</LinearLayout>
If you want save battery, select "Satelite map" from map menu and reduce the brightness of the display.


Black and white bitmap image pictures, gray scale colormatrix 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);
canvas.drawBitmap(bitmapOrg, 10, 10, paint);
int width, height;
ColorMatrix cm = new ColorMatrix(
new float[]{
0.5f,0.5f,0.5f,0,0,
0.5f,0.5f,0.5f,0,0,
0.5f,0.5f,0.5f,0,0,
0,0,0,1,0,0,
0,0,0,0,1,0
});
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
int h = bitmapOrg.getHeight();
//canvas.drawBitmap(bitmapOrg, 10, 10, paint);
canvas.drawBitmap(bitmapOrg, 10, 10 + h + 10, paint);
}
}
}

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.GREEN);
Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
Canvas c = new Canvas(b);
c.drawRect(0, 0, 200, 200, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
paint.setTextSize(40);
paint.setTextScaleX(1.f);
paint.setAlpha(0);
paint.setAntiAlias(true);
c.drawText("Your text", 30, 40, paint);
paint.setColor(Color.RED);
canvas.drawBitmap(b, 10,10, paint);
}
}
}

Editace: 2014-02-15 20:48:27
Počet článků v kategorii: 396
Url:android-startup-tutorial-for-developers-video
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