Android package the project into a jar package, androidjar

Android package the project into a jar package, androidjar

Package Android into a jar package for users. You can use the java reflection technology to obtain the corresponding id, so that users can easily replace what they need.

1. Create an Android project: ActivityLibrary. This is the project that needs to be packaged into a jar package:

2. The role of the MResource class is to use J2SE reflection technology to obtain the corresponding ID resources. The Android SDK also provides the method for obtaining Id resources: getResources (). getIdentifier ("main_activity", "layout", getPackageName ());

Check the MResource code:

Package com. example. activitylibrary; import android. content. context;/*** obtain its ID value based on the resource name * @ author howlaa */public class MResource {// obtain the 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;} // obtain the ID array public static int [] getIdsByNam E (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. Create activity_main.xml in layout:

<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. Check 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. We compress the ActivityLibrary project into a Jar package. Right-click the project ---> Export ----> Java ---> JAR file ----> Next, as shown in figure

You only need the code in SRC. Remove others

6. Create a project APP2 and use the jar package. Copy the exported jar package to libs.

7. If we want to use the mainactivity interface in the previous project: We can have a jump code here:

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

8. Register mainActivity of activitylibrary in mainfest. xml:

<?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>

Complete.