Android高手进阶教程(五)之----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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<?xmlversion="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>
<?xmlversion="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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<?xmlversion="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"
>
<ImageViewandroid:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_marginRight="10dp"
/>
<TextViewandroid:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:textColor="#FFF"
/>
</LinearLayout>
<?xmlversion="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"
>
<ImageViewandroid:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_marginRight="10dp"
/>
<TextViewandroid: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;
publicclass LayoutInflaterDemo extends Activity implements
OnClickListener {
private Button button;
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
 setContentView(R.layout.main);
 button = (Button)findViewById(R.id.button);
 button.setOnClickListener(this);
 }
@Override
publicvoid onClick(View v) {
 showCustomDialog();
 }
publicvoid 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;
publicclass LayoutInflaterDemo extends Activity implements
OnClickListener {
private Button button;
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
 setContentView(R.layout.main);
 button = (Button)findViewById(R.id.button);
 button.setOnClickListener(this);
 }
@Override
publicvoid onClick(View v) {
 showCustomDialog();
 }
publicvoid 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。

好今天就到此为止，睡觉了，大家有什么不明白的请留言~谢谢!