Android 开发笔记___RelativeLayout

xml文件实现

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="500dp" >

     <Button
         android:id="@+id/btn_center"
         style="@style/btn_relative"
         android:layout_centerInParent="true"
         android:text="我在中间" />

     <Button
         android:id="@+id/btn_center_horizontal"
         style="@style/btn_relative"
         android:layout_centerHorizontal="true"
         android:text="我在水平中间" />

     <Button
         android:id="@+id/btn_center_vertical"
         style="@style/btn_relative"
         android:layout_centerVertical="true"
         android:text="我在垂直中间" />

     <Button
         android:id="@+id/btn_parent_left"
         style="@style/btn_relative"
         android:layout_marginTop="100dp"
         android:layout_alignParentLeft="true"
         android:text="我跟上级左边对齐" />

     <Button
         android:id="@+id/btn_parent_top"
         style="@style/btn_relative"
         android:layout_width="120dp"
         android:layout_alignParentTop="true"
         android:text="我跟上级顶部对齐" />

     <Button
         android:id="@+id/btn_parent_right"
         style="@style/btn_relative"
         android:layout_marginTop="100dp"
         android:layout_alignParentRight="true"
         android:text="我跟上级右边对齐" />

     <Button
         android:id="@+id/btn_parent_bottom"
         style="@style/btn_relative"
         android:layout_width="120dp"
         android:layout_alignParentBottom="true"
         android:layout_centerHorizontal="true"
         android:text="我跟上级底部对齐" />

     <Button
         android:id="@+id/btn_left_bottom"
         style="@style/btn_relative"
         android:layout_toLeftOf="@+id/btn_parent_bottom"
         android:layout_alignTop="@+id/btn_parent_bottom"
         android:text="我在底部左边" />

     <Button
         android:id="@+id/btn_right_bottom"
         style="@style/btn_relative"
         android:layout_toRightOf="@+id/btn_parent_bottom"
         android:layout_alignBottom="@+id/btn_parent_bottom"
         android:text="我在底部右边" />

     <Button
         android:id="@+id/btn_above_center"
         style="@style/btn_relative"
         android:layout_above="@+id/btn_center"
         android:layout_alignLeft="@+id/btn_center"
         android:text="我在中间上面" />

     <Button
         android:id="@+id/btn_below_center"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_center"
         android:layout_alignRight="@+id/btn_center"
         android:text="我在中间下面" />

 </RelativeLayout>

java

 package com.example.alimjan.hello_world;

 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;

 import com.example.alimjan.hello_world.two.class__2_1;

 /**
  * Created by alimjan on 7/2/2017.
  */

 public class class_3_1_1 extends AppCompatActivity{
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.code_3_1_1);
     }

     public static void startHome(Context mContext) {
         Intent intent = new Intent(mContext, class_3_1_1.class);
         mContext.startActivity(intent);
     }
 }

代码实现

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/rl_content"
     android:layout_width="match_parent"
     android:layout_height="match_parent" >

     <TextView
         style="@style/btn_relative"
         android:layout_alignParentTop="true"
         android:layout_centerHorizontal="true"
         android:text="点击按钮添加视图，长按视图删除自身" />

     <Button
         android:id="@+id/btn_add_left"
         style="@style/btn_relative"
         android:layout_marginTop="80dp"
         android:layout_centerHorizontal="true"
         android:text="添加左边视图" />

     <Button
         android:id="@+id/btn_add_above"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_left"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加上方视图" />

     <Button
         android:id="@+id/btn_add_right"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_above"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加右边视图" />

     <Button
         android:id="@+id/btn_add_below"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_right"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加下方视图" />

     <Button
         android:id="@+id/btn_add_center"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_below"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加中间视图" />

     <Button
         android:id="@+id/btn_add_parent_left"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_center"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加上级左侧对齐视图" />

     <Button
         android:id="@+id/btn_add_parent_top"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_parent_left"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加上级顶部对齐视图" />

     <Button
         android:id="@+id/btn_add_parent_right"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_parent_top"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加上级右侧对齐视图" />

     <Button
         android:id="@+id/btn_add_parent_bottom"
         style="@style/btn_relative"
         android:layout_below="@+id/btn_add_parent_right"
         android:layout_alignLeft="@+id/btn_add_left"
         android:text="添加上级底部对齐视图" />

 </RelativeLayout>

 package com.example.alimjan.hello_world;

 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.view.View;
 import android.widget.RelativeLayout;

 /**
  * Created by alimjan on 7/2/2017.
  */

 public class class_3_1_1_code extends AppCompatActivity implements View.OnClickListener {

     private RelativeLayout rl_content;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.code_3_1_1_code);

         rl_content = (RelativeLayout) findViewById(R.id.rl_content);
         findViewById(R.id.btn_add_left).setOnClickListener(this);
         findViewById(R.id.btn_add_above).setOnClickListener(this);
         findViewById(R.id.btn_add_right).setOnClickListener(this);
         findViewById(R.id.btn_add_below).setOnClickListener(this);
         findViewById(R.id.btn_add_center).setOnClickListener(this);
         findViewById(R.id.btn_add_parent_left).setOnClickListener(this);
         findViewById(R.id.btn_add_parent_top).setOnClickListener(this);
         findViewById(R.id.btn_add_parent_right).setOnClickListener(this);
         findViewById(R.id.btn_add_parent_bottom).setOnClickListener(this);
     }

     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btn_add_left) {
             addNewView(RelativeLayout.LEFT_OF, RelativeLayout.ALIGN_TOP, v.getId());
         } else if (v.getId() == R.id.btn_add_above) {
             addNewView(RelativeLayout.ABOVE, RelativeLayout.ALIGN_LEFT, v.getId());
         } else if (v.getId() == R.id.btn_add_right) {
             addNewView(RelativeLayout.RIGHT_OF, RelativeLayout.ALIGN_BOTTOM, v.getId());
         } else if (v.getId() == R.id.btn_add_below) {
             addNewView(RelativeLayout.BELOW, RelativeLayout.ALIGN_RIGHT, v.getId());
         } else if (v.getId() == R.id.btn_add_center) {
             addNewView(RelativeLayout.CENTER_IN_PARENT, -1, rl_content.getId());
         } else if (v.getId() == R.id.btn_add_parent_left) {
             addNewView(RelativeLayout.ALIGN_PARENT_LEFT, RelativeLayout.CENTER_VERTICAL, rl_content.getId());
         } else if (v.getId() == R.id.btn_add_parent_top) {
             addNewView(RelativeLayout.ALIGN_PARENT_TOP, RelativeLayout.CENTER_HORIZONTAL, rl_content.getId());
         } else if (v.getId() == R.id.btn_add_parent_right) {
             addNewView(RelativeLayout.ALIGN_PARENT_RIGHT, -1, rl_content.getId());
         } else if (v.getId() == R.id.btn_add_parent_bottom) {
             addNewView(RelativeLayout.ALIGN_PARENT_BOTTOM, -1, rl_content.getId());
         }
     }

     private void addNewView(int firstAlign, int secondAlign, int referId) {
         View v = new View(this);
         v.setBackgroundColor(0xaa66ff66);
         RelativeLayout.LayoutParams rl_params = new RelativeLayout.LayoutParams(100, 100);
         rl_params.addRule(firstAlign, referId);
         if (secondAlign >= 0) {
             rl_params.addRule(secondAlign, referId);
         }
         v.setLayoutParams(rl_params);
         v.setOnLongClickListener(new View.OnLongClickListener() {
             @Override
             public boolean onLongClick(View vv) {
                 rl_content.removeView(vv);
                 return true;
             }
         });
         rl_content.addView(v);
     }

     public static void startHome(Context mContext) {
         Intent intent = new Intent(mContext, class_3_1_1_code.class);
         mContext.startActivity(intent);
     }

 }