Android_学习笔记.doc

Activity初步
Activity的实现:1.继承类Activity2.重写onCreate()方法3.每一个Activity都要在AndroidManifest.xml中进行配置4.在Activity上添加控件例：publicclassMyActivityextendsActivity{@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);TextViewmyTextView=(TextView)findViewById(R.id.myTextView);ButtonmyButton=(Button)findViewById(R.id.myButton);myTextView.setText("我的第一个TextView");myButton.setText("我的第一个Button");}}多个Activity之间的关系1.跳转方法：startActivity(Intentintent)一个Intent对象包含一组信息:1.Componentname2.Action3.Data4.Category5.Extras6.FlagsActivity之间的跳转publicclassActivity02extendsActivity{privateButtonmyButton=null;publicvoidonCreate(BundlesaveInstanceState){super.onCreate(saveInstanceState);setContentView(R.layout.main);myButton=(Button)findViewById(R.id.myButton);myButton.setOnClickListener(newMyButtonListener());}classMyButtonListenerimplementsOnClickListener{publicvoidonClick(Viewv){Intentintent=newIntent();intent.putExtra("testIntent","123");//传递数据intent.setClass(Activity02.this,OtherActivity.class);Activity02.this.startActivity(intent);}}}publicclassOtherActivityextendsActivity{privateTextViewmyTextView=null;protectedvoidonCreate(BundlesaveInstanceState){super.onCreate(saveInstanceState);setContentView(R.layout.main);Intentintent=getIntent();Stringvalue=intent.getStringExtra("testIntent");//取出数据myTextView=(TextView)findViewById(R.id.myTextView);//myTextView.setText(R.string.other);myTextView.setText(value);}}

布局文件属性的说明
相对布局文件属性说明：android:layout_above将该控件的底部置于给定的ID的控件之上android:layout_below将该控件的底部置于给定的ID的控件之下android:layout_toLeftOf将该控件的右边缘和给定ID的控件的左边对齐android:layout_toRightOf将该控件的左边缘和给定ID的控件的右边对齐android:layout_alignBaseline该控件的baseline和给定ID的控件的baseline对齐android:layout_alignBotton该控件的底部和给定ID的控件的底部对齐android:layout_alignLeft该控件的左边和给定ID的控件的左边对齐android:layout_alignRight该控件的右边和给定ID的控件的右边对齐android:layout_alignTop该控件的顶部和给定ID的控件的顶部对齐android:layout_alignParentBottom如为true则将该控件的底部父控件的底部对齐android:layout_alignParentLeft如为true则将该控件的底部父控件的左部对齐android:layou