将Android打包成jar包供人使用,可利用java的反射技术,获取相应的id.方便使用者替换自己所需要的。
1.新建Android项目:ActivityLibrary,这就是需要我们打包成jar包的项目:
2.MResource这个类的作用,就是利用J2SE反射技术获取相应的ID资源。Android SDK也提供了获取Id资源的方法:getResources().getIdentifier("main_activity", "layout", getPackageName());
看下MResource的代码:
package com.example.activitylibrary;
import android.content.Context;
/**
* 根据资源的名字获取其ID值
* @author howlaa
*/
public class MResource {
//根据名称获取ID
public static int getIdByName(Context context, String className, String name) {
String packageName = context.getPackageName();
Class r = null;
int id = 0;
try{
r = Class.forName(packageName + ".R");
Class[] classes = r.getClasses();
Class desireClass = null;
for (int i = 0; i < classes.length; ++i) {
if (classes[i].getName().split("\\$")[1].equals(className)) {
desireClass = classes[i];
break;
}
}
if (desireClass != null)
id = desireClass.getField(name).getInt(desireClass);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
return id;
}
//获取ID数组
public static int[] getIdsByName(Context context, String className, String name) {
String packageName = context.getPackageName();
Class r = null;
int[] ids = null;
try {
r = Class.forName(packageName + ".R");
Class[] classes = r.getClasses();
Class desireClass = null;
for (int i = 0; i < classes.length; ++i) {
if (classes[i].getName().split("\\$")[1].equals(className)) {
desireClass = classes[i];
break;
}
}
if ((desireClass != null) && (desireClass.getField(name).get(desireClass) != null) && (desireClass.getField(name).get(desireClass).getClass().isArray()))
ids = (int[])desireClass.getField(name).get(desireClass);
}
catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
return ids;
}
}
3.在layout下新建activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/button1" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView1"
android:layout_marginTop="28dp"
android:src="@drawable/ic_launcher" />
</RelativeLayout>
4.看下mainactivity:
package com.example.activitylibrary;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
public class MainActivity extends Activity {
String msg = "hello bitch";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(MResource.getIdByName(getApplication(), "layout", "activity_main"));
TextView mTextView = (TextView) findViewById(MResource.getIdByName(getApplication(), "id", "textView1"));
mTextView.setText(msg);
Button mButton = (Button) findViewById(MResource.getIdByName(getApplication(), "id", "button1"));
mButton.setText(msg);
mButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getApplication(), msg, Toast.LENGTH_SHORT).show();
}
});
}
}
5. 我们将ActivityLibrary工程打成Jar包。右键项目--->Export---->Java--->JAR file---->Next如下图
只需要SRC里面的代码就可以了。其他的去掉
6.新建一个项目APP2,使用刚才的jar包。把刚才导出的jar包拷贝到libs下面,把原来的资源文件拷贝过去。或者自己新建一个layout的资源文件,id要和之前的对应。
7.假如我们想使用上个项目中的mainactivity界面:我们可以在此有个跳转的代码:
public void btnClick(View view){
Intent intent = new Intent();
intent.setClassName(getApplication(), "com.example.activitylibrary.MainActivity");
startActivity(intent);
}
8.在mainfest.xml中注册activitylibrary的mainActivity:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.app2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.app2.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.activitylibrary.MainActivity"></activity>
</application>
</manifest>
完毕。