在代码中，通过new的方式，添加控件

今天需要在代码中动态的给一个布局添加一个imageview，现在把方法记录如下。直接看demo代码

  1. //创建容器
  2.         final LinearLayout layout = new LinearLayout(this);
  3.         //设置背景
  4.         layout.setBackgroundColor(0x7700ffff);
  5.         //设置垂直排列
  6.         layout.setOrientation(LinearLayout.VERTICAL);
  7.         //设置控件水平居中
  8.         layout.setGravity(Gravity.CENTER_HORIZONTAL);
  9.         //创建属性
  10.         LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(300,300);
  11.         addContentView(layout, layoutParams);
  13.         
  14.         //创建控件image
  15.         ImageView imageView = new ImageView(this);
  16.         imageView.setBackgroundColor(0xffff0000);
  17.         LinearLayout.LayoutParams layoutParams2 = new LinearLayout.LayoutParams(100,100);
  18.         
  19.         //设置子控件的margin数值
  20.         layoutParams2.leftMargin=50;
  21.         layoutParams2.topMargin=50;
  22.         //添加到容器
  23.         layout.addView(imageView, layoutParams2);
  24.         
  25.         //创建textiew
  26.         TextView textView = new TextView(this);
  27.         textView.setText("textview");
  28.         LinearLayout.LayoutParams layoutParams3 = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
    　　　　 //设置相对父容器的位置 
    //layoutParams.gravity = Gravity.END; 
    //设置自身内容相对自身位置 
    //button.setGravity(Gravity.END);
  29.         //设置padding
  30.         layoutParams3.leftMargin=70;
  31.         layoutParams3.topMargin=20;
  32.         layout.addView(textView, layoutParams3);

 

看效果图

其实，代码中动态添加view，就跟使用xml一样的，xml中有的属性，都可以通过代码设置实现。这些属性，要么通过创建的控件(imageview)方法来设，要么就是通过

  1. LayoutParams

其实，在这个类里面主要含有的是margin相关属性，下面是它源码的一部分

  1.             this.leftMargin = source.leftMargin;
  2.             this.topMargin = source.topMargin;
  3.             this.rightMargin = source.rightMargin;
  4.             this.bottomMargin = source.bottomMargin;
  5.             this.startMargin = source.startMargin;
  6.             this.endMargin = source.endMargin;

 还有另外一个常用的relativelayout，我们也写一个小的demo看下

xml

  1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.     xmlns:tools="http://schemas.android.com/tools"
  3.     android:layout_width="match_parent"
  4.     android:id="@+id/aaa"
  5.     android:layout_height="match_parent"
  6.     tools:context="com.example.testcode.MainActivity" >
  7.  
  8.     <TextView 
  9.         android:id="@+id/tv"
  10.         android:text="origin text"
  11.         android:layout_width="100dp"
  12.         android:layout_height="100dp"
  13.         android:background="#ff0000"
  14.         />
  15.  
  16. </RelativeLayout>

代码如下

  1. package com.example.testcode;
  2. import android.app.Activity;
  3. import android.os.Bundle;
  4. import android.view.Menu;
  5. import android.view.MenuItem;
  6. import android.widget.Button;
  7. import android.widget.LinearLayout.LayoutParams;
  8. import android.widget.RelativeLayout;
  9. import android.widget.TextView;
  11. public class MainActivity extends Activity {
  12.     private TextView textView;
  13.     private RelativeLayout aaaLayout;
  15.     @Override
  16.     protected void onCreate(Bundle savedInstanceState) {
  17.         super.onCreate(savedInstanceState);
  18.         setContentView(R.layout.activity_main);
  19.         textView = (TextView) findViewById(R.id.tv);
  20.         aaaLayout = (RelativeLayout) findViewById(R.id.aaa);
  21.         Button button = new Button(this);
  22.         RelativeLayout.LayoutParams layoutParams_button = new RelativeLayout.LayoutParams(
  23.                 100, 100);    
  24.         RelativeLayout relativeLayout = new RelativeLayout(this);
  25.         //LinearLayout这个方法有三个参数的，加了一个权重在里面,RelativeLayout就不存在了
  26.         //LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(width, height, weight);
  27.         RelativeLayout.LayoutParams layoutParams_text = new RelativeLayout.LayoutParams(
  28.                 LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);    
  29.         //设置控件相对R.id.tv位置
  30.         //layoutParams_text.addRule(RelativeLayout.BELOW, R.id.tv);
  31.         //设置控件相对父容器位置
  32.         layoutParams_text.addRule(RelativeLayout.CENTER_HORIZONTAL);
  33.         layoutParams_text.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
  34.         //layoutParams_text.addRule(RelativeLayout.CENTER_IN_PARENT);
  35.         relativeLayout.addView(button, layoutParams_button);
  36.         aaaLayout.addView(relativeLayout, layoutParams_text);
  37.     }
  39.     @Override
  40.     public boolean onCreateOptionsMenu(Menu menu) {
  41.         // Inflate the menu; this adds items to the action bar if it is present.
  42.         getMenuInflater().inflate(R.menu.main, menu);
  43.         return true;
  44.     }
  46.     @Override
  47.     public boolean onOptionsItemSelected(MenuItem item) {
  48.         // Handle action bar item clicks here. The action bar will
  49.         // automatically handle clicks on the Home/Up button, so long
  50.         // as you specify a parent activity in AndroidManifest.xml.
  51.         int id = item.getItemId();
  52.         if (id == R.id.action_settings) {
  53.             return true;
  54.         }
  55.         return super.onOptionsItemSelected(item);
  56.     }
  57. }

我们看下效果




 

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