Known Direct Subclasses Button,CheckedTextView,Chronometer,DigitalClock,EditText,TextClock
Button
Represents a push-button widget.?
CheckedTextView
An extension to TextView that supports the Checkable interface.?
Chronometer
Class that implements a simple timer.?
DigitalClock
This class was deprecated in API level 17. It is recommended you useTextClock instead.?
EditText
EditText is a thin veneer over TextView that configures itself to be editable.?
TextClock
TextClock can display the current date and/or time as a formatted string.?
Known Indirect Subclasses AutoCompleteTextView,CheckBox,CompoundButton,ExtractEditText,MultiAutoCompleteTextView,RadioButton,Switch,ToggleButton
1、fill_parent與match_parentAndroid2.2開始兩者相同，2.2之前用fill_parent，官方推薦match_parent。2、layout_gravity與gravity2.1）gravity：指定控件中文字的對齊方式。layout_gravity：指定控件在所在布局中的對齊方式。LinearLayout中：orientation：vertical時：layout_gravity水平方向的設(shè)置有效：left/right/center_horizontalorientation:horiaontal時：layout_gravity垂直方向設(shè)置有效：top/bottom/center_vertical. ?center 都可以用，總有一個方向生效2.2）想要設(shè)置某個控件居底，可以在空間外加一層LinearLayout并設(shè)置其gravity為bottom.
<LinearLayout
...
android:gravity="bottom"
...><Button
....../>
</LinearLayout>3、Button點擊事件
3.1)XML:?<Button
...
android:onClick="onClick"/><!--點擊事件的方法名--> public void onClick(View view){
}3.2)?
login_btn.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view){}}});//匿名類的方式3.3)
public class MainActivity extends Activity implements onClickListener{@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);Button button = (Button)findViewById(R.id.button);button.setOnClickListener(this);
}@Overridepublic void onClick(View view){
}
}
3.4)
Button Btn = (Button) findViewById(R.id.button); Btn2.setOnClickListener(listener);//設(shè)置監(jiān)聽 } Button.OnClickListener listener = new Button.OnClickListener(){//創(chuàng)建監(jiān)聽對象 public void onClick(View v){ } }; 4、EditText
當(dāng)需要輸入EditText中的內(nèi)容過多時，可以指定最大行數(shù)，當(dāng)達(dá)到最大行數(shù)時文本就會往上滾動。
android:maxLines="2"5、ProgressBar/AlertDialog/ProgressDialog <ProgressBarandroid:id="@+id/progressBar"android:layout_width="wrap_content"android:layout_height="wrap_content"/><!-- 可以設(shè)置style="?android:attr/progressBarStyleHorizontal"android:max="100"-->//AlertDialog/ProgressDialog@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();switch(id){case R.id.alertDialog:AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);alertDialog.setTitle("Warning");alertDialog.setMessage("This is a warning");alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {// TODO Auto-generated method stub}});alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {// TODO Auto-generated method stub}});alertDialog.show();break;case R.id.progressDialog:ProgressDialog progressDialog = new ProgressDialog(this);progressDialog.setTitle("ProgressDialog");progressDialog.setMessage("loading...");progressDialog.show();break;default:}return super.onOptionsItemSelected(item);}
