Android Development Snippets

Common tasks in Android development and the required code snippet  

Print and Debug:

Log.d("Tag", "Message");
Toast.makeText(MainActivity.this, "hello", Toast.LENGTH_LONG).show();

Updating component

TextView t=(TextView)findViewById(R.id.textViewId);
t.setText("String");

Start activity

Intent in=new Intent("action name");
startActivity(in)

Start Activity and send parameters:

Intent in=new Intent("mabel.xyz");
in.putExtra("num", 100);
startActivityForResult(in, 0);

Return value from Activity:

Intent res=new Intent();
res.putExtra("res", num+20);
setResult(20, res);
finish(); // To close the Activity - optional

Get the Activity result:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
	super.onActivityResult(requestCode, resultCode, data);
	int res=data.getIntExtra("res", 99);
}

Dialog Example

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are You Sure?")
	       .setCancelable(false)
	       .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
	           public void onClick(DialogInterface dialog, int id) {
                            // code for yes
		           }
			       })
	       .setNegativeButton("No", new  DialogInterface.OnClickListener() {
	           public void onClick(DialogInterface dialog, int id) {
		                dialog.cancel();
		           }
		});
AlertDialog alert = builder.create();
alert.show();

Creating GUI from XML in runtime:

ToggleButton button = (ToggleButton) act.getLayoutInflater().inflate(
				R.layout.template_my_button, null);


//  The XML:
//  <ToggleButton xmlns:android="http://schemas.android.com/apk/res/android"
//                             style="@style/switch_icon_style"
//                             />