【转】Android 中LayoutInflater的使用

大家好我们这一节讲的是LayoutInflater的使用,在实际开发种LayoutInflater这个类还是非常有用的,它的作用类似于 findViewById(),

不同点是LayoutInflater是用来找layout下xml布局文件，并且实例化！而findViewById()是找具体xml下的具体 widget控件(如:Button,TextView等)。

为了让大家容易理解我做了一个简单的Demo,主布局main.xml里有一个TextView和一个Button，当点击Button，出现 Dialog,而这个Dialog的布局方式是我们在layout目录下定义的custom_dialog.xml文件(里面左右分布，左边 ImageView,右边TextView)。

效果图如下:

下面我将详细的说明Demo的实现过程:

1、新建一个 Android工程，我们命名为LayoutInflaterDemo.

2、修改main.xml布局，里面主要在原来基础上增加了一个Button.代码如下:

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<?xml version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="ShowCustomDialog"
    />
</LinearLayout>
<?xml version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
<Button
 android:id="@+id/button"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="ShowCustomDialog"
 />
</LinearLayout>

3.定义对话框的布局方式，我们在layout目录下，新建一个名为 custom_dialog.xml文件具体代码如下:

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<?xml version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              android:padding="10dp"
              >
    <ImageView android:id="@+id/image"
               android:layout_width="wrap_content"
               android:layout_height="fill_parent"
               android:layout_marginRight="10dp"
               />
    <TextView android:id="@+id/text"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:textColor="#FFF"
              />
</LinearLayout>
<?xml version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              android:padding="10dp"
              >
    <ImageView android:id="@+id/image"
               android:layout_width="wrap_content"
               android:layout_height="fill_parent"
               android:layout_marginRight="10dp"
               />
    <TextView android:id="@+id/text"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:textColor="#FFF"
              />
</LinearLayout>

4.修改主程序LayouInflaterDemo.java代码如下:

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package com.android.tutor;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
public class LayoutInflaterDemo extends Activity implements
OnClickListener {

    private Button button;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        button = (Button)findViewById(R.id.button);
        button.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {

        showCustomDialog();
    }

    public void showCustomDialog()
    {
        AlertDialog.Builder builder;
        AlertDialog alertDialog;
        Context mContext = LayoutInflaterDemo.this;

        //下面俩种方法都可以
        ////LayoutInflater inflater = getLayoutInflater();
        LayoutInflater inflater = (LayoutInflater)
mContext.getSystemService(LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.custom_dialog,null);
        TextView text = (TextView) layout.findViewById(R.id.text);
        text.setText("Hello, Welcome to Mr Wei's blog!");
        ImageView image = (ImageView) layout.findViewById(R.id.image);
        image.setImageResource(R.drawable.icon);
        builder = new AlertDialog.Builder(mContext);
        builder.setView(layout);
        alertDialog = builder.create();
        alertDialog.show();
    }
}
package com.android.tutor;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
public class LayoutInflaterDemo extends Activity implements
OnClickListener {

 private Button button;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        button = (Button)findViewById(R.id.button);
        button.setOnClickListener(this);
    }
 @Override
 public void onClick(View v) {

  showCustomDialog();
 }

 public void showCustomDialog()
 {
  AlertDialog.Builder builder;
  AlertDialog alertDialog;
  Context mContext = LayoutInflaterDemo.this;

  //下面俩种方法都可以
  ////LayoutInflater inflater = getLayoutInflater();
  LayoutInflater inflater = (LayoutInflater)
mContext.getSystemService(LAYOUT_INFLATER_SERVICE);
  View layout = inflater.inflate(R.layout.custom_dialog,null);
  TextView text = (TextView) layout.findViewById(R.id.text);
  text.setText("Hello, Welcome to Mr Wei's blog!");
  ImageView image = (ImageView) layout.findViewById(R.id.image);
  image.setImageResource(R.drawable.icon);
  builder = new AlertDialog.Builder(mContext);
  builder.setView(layout);
  alertDialog = builder.create();
  alertDialog.show();
 }
}

5、最后执行之，点击Button，将得到上述效果。