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
Context cnt = MyStorage.getContext();
}
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Copy file to another
Copy and compress file
File path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File file = new File(path, "MyPicture.jpg");
// the Pictures directory exists?
path.mkdirs();
InputStream is = getResources().openRawResource(R.drawable.flower_blue);
OutputStream os = new FileOutputStream(file);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
Copy and compress file
Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
R.drawable.flower_blue);
try {
FileOutputStream out = new FileOutputStream("new_bitmap.jpg");
bitmapOrg.compress(Bitmap.CompressFormat.JPEG, 90, out);
} catch (Exception e) {
e.printStackTrace();
Log.e("saveBitmap", e.getMessage());
}
Html.fromHtml(String) does not support all HTML tags. For example < ul > and < li > are not supported.
Try this source code as a substitute for HTML List Tags.
Result:
• Cessnock
• Dubbo
• Goulburn
• Grafton
• Lithgow
• Liverpool
• Newcastle
Supported tags
a
b
big
blockquote
br
cite
dfn
div
em
font
h1-h6
i
img
p
small
strong
sub
sup
tt
u
Try this source code as a substitute for HTML List Tags.
String str =
"• Cessnock<br />"
+"• Dubbo<br />"
+"• Goulburn<br />"
+"• Grafton<br />"
+"• Lithgow<br />"
+"• Liverpool<br />"
+"• Newcastle<br />"
;
textview.setText(Html.fromHtml(str));
Result:
• Cessnock
• Dubbo
• Goulburn
• Grafton
• Lithgow
• Liverpool
• Newcastle
Supported tags
bla.com
a
b
big
blockquote
br
cite
dfn
div
em
font
h1-h6
i
img
p
small
strong
sub
sup
tt
u
Android app setup preferences, settings, open, read, write, onStop(), onPause(), getSharedPreferences(), SharedPreferences.Editor getInt(), getBoolean(), getString() , putInt(), putString(), putBoolean() example source code.
import android.content.SharedPreferences;
public class MainClass extends Activity {
public static final String PREFERENCES_NAME = "MyPrefsFile";
String myNewString;
int myNewInt;
Boolean myNewBool;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// read old settings if exist
SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
String sDefault = "Hello!";
String sStringFromPrefFile = settings.getString("myString", sDefault); // new text or default Hello!
int nDefaultIndex = 2; //
int nIndexFromPrefFile = settings.getInt("myInt", nDefaultIndex); // 4 or default 2
Boolean bDefault = false;
Boolean bFromPrefFile = settings.getBoolean("silentMode", bDefault); // true or default false
// new settings will saved in onStop or onPause
myNewString = "new text";
myNewInt = 4;
myNewBool = true;
}
@Override
protected void onPause() {
super.onPause();
Toast.makeText(getApplicationContext(), "onPause "
, Toast.LENGTH_SHORT).show();
savePreferences();
}
@Override
protected void onStop() {
super.onStop();
savePreferences();
}
/**save settings*/
public void savePreferences(){
try {
SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("myString", myNewString);
editor.putInt("nMyInt", myNewInt);
editor.putBoolean("silentMode", myNewBool); //
editor.commit();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Bitmap Width, Height without memory allocation:
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.myimage, options);
// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though Bitmap is null
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;
How add pair of strings to Hashtable, how get pair key value from Hashtable, how split string, basic Java Android example.
MainClass.java
MainClass.java
import java.util.Enumeration;
import java.util.Hashtable;
public class MainClass {
public static void main(String[] arg) {
// english;germany dictionary
String[] arrayOfString = { "one;eine", "two;zwei", "three;drei" };
Hashtable<String, String> hashTable = new Hashtable<String, String>();
for(String s: arrayOfString){
String[] array = s.split(";");
String sKey ="", sValue="";
if(array.length > 1){
sKey = array[0]; sValue = array[1];
hashTable.put(sKey, sValue);
}
}
Enumeration<String> enumer = hashTable.keys();
while (enumer.hasMoreElements()) {
String keyFromTable = (String) enumer.nextElement();
// get Returns the value to which the specified key is mapped,
// or null if this map contains no mapping for the key
System.out.println(keyFromTable + " = " + hashTable.get(keyFromTable));
}
}
}
/*
two = zwei
one = eine
three = drei
*/
Editace: 2011-10-15 08:31:19
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Url:get-context-java-android-example