Android初学习 - 在布局中动态添加view的两种方法

       一、说明

添加视图文件的时候有两种方式:1、通过在xml文件定义layout；2、java代码编写

二、前言说明

1.构造xml文件

2.LayoutInflater

提到addview，首先要了解一下LayoutInflater类。这个类最主要的功能就是实现将xml表述的layout转化为View的功能。为了便于理解，我们可以将它与findViewById()作一比较，二者都是实例化某一对象，不同的是findViewById()是找xml布局文件下的具体widget控件实例化，而LayoutInflater找res/layout/下的xml布局文件来实例化的。

(1)创建

LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);或

LayoutInflater inflater = LayoutInflater.from(Activity.this);或

LayoutInflater inflater = getLayoutInflater();

这三种方法本质是相同的。

(2)inflate()

用LayoutInflater.inflate() 将LayOut文件转化成VIew。

View view = inflater.inflate(R.layout.block_gym_album_list_item, null);

3.添加视图文件

三、步骤
1、通过在xml文件定义layout(block_gym_album_list_item.xml)

<!--?xml version="1.0" encoding="utf-8"?-->
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:core="http://schemas.android.com/apk/res/com.gxtag.gym" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:padding="5dp">

<imageview android:id="@+id/iv_head_album" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/defaulthead">

</imageview></linearlayout>
2、main.xml
<!--?xml version="1.0" encoding="utf-8"?-->
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/ll_parent" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical">
<include android:layout_width="fill_parent" android:layout_height="wrap_content" layout="@layout/block_head_back"></include></linearlayout>3、DynamicViewActivity.xml

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;

import com.gxtag.gym.R;
import com.icq.app.widget.StatedButton;

public class DynamicViewActivity extends Activity implements OnClickListener{

private Context mContext;
private TextView mTv_title;
private String title = "动态添加布局";
private StatedButton mSbtn_back;
private LinearLayout mLl_parent;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamic);
mContext=this;
initView();
mLl_parent.addView(addView1());
mLl_parent.addView(addView2());

}

private void initView() {
// TODO 初始化视图
mLl_parent=(LinearLayout) findViewById(R.id.ll_parent);
mTv_title = (TextView) findViewById(R.id.tv_title);
mTv_title.setText(String.format(String.format(
getResources().getString(R.string.title), title)));
mSbtn_back = (StatedButton) findViewById(R.id.sbtn_navback);
mSbtn_back.setOnClickListener(this);

}

private View addView1() {
// TODO 动态添加布局(xml方式)
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
// LayoutInflater inflater1=(LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// LayoutInflater inflater2 = getLayoutInflater();
LayoutInflater inflater3 = LayoutInflater.from(mContext);
View view = inflater3.inflate(R.layout.block_gym_album_list_item, null);
view.setLayoutParams(lp);
return view;

}

private View addView2() {
// TODO 动态添加布局(java方式)
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
LinearLayout view = new LinearLayout(this);
view.setLayoutParams(lp);//设置布局参数
view.setOrientation(LinearLayout.HORIZONTAL);// 设置子View的Linearlayout// 为垂直方向布局
//定义子View中两个元素的布局
ViewGroup.LayoutParams vlp = new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
ViewGroup.LayoutParams vlp2 = new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);

TextView tv1 = new TextView(this);
TextView tv2 = new TextView(this);
tv1.setLayoutParams(vlp);//设置TextView的布局
tv2.setLayoutParams(vlp2);
tv1.setText("姓名:");
tv2.setText("李四");
tv2.setPadding(calculateDpToPx(50), 0, 0, 0);//设置边距
view.addView(tv1);//将TextView 添加到子View 中
view.addView(tv2);//将TextView 添加到子View 中
return view;
}

private int calculateDpToPx(int padding_in_dp){
final float scale = getResources().getDisplayMetrics().density;
return (int) (padding_in_dp * scale + 0.5f);
}

@Override
public void onClick(View v) {
// TODO 控件单击事件
switch (v.getId()) {
case R.id.sbtn_navback:
this.finish();
break;
default:
break;
}
}

}