TextView

extends View

implements ViewTreeObserver.OnPreDrawListener

java.lang.Object
↳	android.view.View
	↳	android.widget.TextView

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 use`TextClock` 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与match_parent

Android2.2开始两者相同，2.2之前用fill_parent，官方推荐match_parent。

2、layout_gravity与gravity

2.1）gravity：指定控件中文字的对齐方式。

layout_gravity：指定控件在所在布局中的对齐方式。

LinearLayout中：

orientation：vertical时：layout_gravity水平方向的设置有效：left/right/center_horizontal

orientation:horiaontal时：layout_gravity垂直方向设置有效：top/bottom/center_vertical. center 都可以用，总有一个方向生效

2.2）想要设置某个控件居底，可以在空间外加一层LinearLayout并设置其gravity为bottom.

<LinearLayout
...
android:gravity="bottom"
...><Button
....../>
</LinearLayout>

3、Button点击事件

3.1)XML:

<Button
...
android:onClick="onClick"/><!--点击事件的方法名-->

public void onClick(View view){
}

3.2)

 login_btn.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view){}}});//匿名类的方式

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);//设置监听    }  Button.OnClickListener listener = new Button.OnClickListener(){//创建监听对象    public void onClick(View v){    }    };

4、EditText

当需要输入EditText中的内容过多时，可以指定最大行数，当达到最大行数时文本就会往上滚动。

android:maxLines="2"

5、ProgressBar/AlertDialog/ProgressDialog

 <ProgressBarandroid:id="@+id/progressBar"android:layout_width="wrap_content"android:layout_height="wrap_content"/><!-- 可以设置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);}