android將項目打包成jar包使用，androidjar

android將項目打包成jar包使用，androidjar

將Android打包成jar包供人使用，可利用java的反射技術，擷取相應的id.方便使用者替換自己所需要的。

1.建立Android項目：ActivityLibrary，這就是需要我們打包成jar包的項目：

2.MResource這個類的作用，就是利用J2SE反射技術擷取相應的ID資源。Android SDK也提供了擷取Id資源的方法：getResources().getIdentifier("main_activity", "layout", getPackageName());

看下MResource的代碼：

package com.example.activitylibrary;import android.content.Context;/**  * 根據資源的名字擷取其ID值  * @author howlaa */ public class MResource {//根據名稱擷取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;      }        //擷取ID數組    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下建立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";  @Overrideprotected 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.我們將ActivityLibrary工程打成Jar包。右鍵項目--->Export---->Java--->JAR file---->Next如

只需要SRC裡面的代碼就可以了。其他的去掉

6.建立一個項目APP2，使用剛才的jar包。把剛才匯出的jar包拷貝到libs下面。

7.假如我們想使用上個項目中的mainactivity介面：我們可以在此有個跳轉的代碼：

public void btnClick(View view){Intent intent = new Intent();          intent.setClassName(getApplication(), "com.example.activitylibrary.MainActivity");          startActivity(intent);  }

8.在mainfest.xml中註冊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>

完畢。