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;
-
-
-
- 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;
-
-
-
- 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!