PackageManagerService相关类结构

分析

从上图可以看出若想为PackageManagerService添加方法需要进行以下改动 1，在IPackageManager.aidl文件中增加方法的声明； 2，在PackageManager类中增加抽象方法说明； 3，在ApplicationPackageManager中增加方法，具体实现为调用远程PackageManagerService的方法； 4，在PackageManagerService中增加方法的具体实现；

注：由于MockPackageManager类也继承了PackageManager类，故也需要加入一些实现的代码；增加的方法要设置为hide，或者更改API-List加入新增加的方法

Demo

目标：在PackageManagerService加入方法public String getHello();

第一步：在IPackageManager.aidl增加getHello()方法声明

interface IPackageManager {
    PackageInfo getPackageInfo(String packageName, int flags);
    int getPackageUid(String packageName);
    int[] getPackageGids(String packageName);
    
    String[] currentToCanonicalPackageNames(in String[] names);
    String[] canonicalToCurrentPackageNames(in String[] names);

    PermissionInfo getPermissionInfo(String name, int flags);
    
    List<PermissionInfo> queryPermissionsByGroup(String group, int flags);
    
    PermissionGroupInfo getPermissionGroupInfo(String name, int flags);
    
    List<PermissionGroupInfo> getAllPermissionGroups(int flags);
    
    ApplicationInfo getApplicationInfo(String packageName, int flags);

    ActivityInfo getActivityInfo(in ComponentName className, int flags);

    ActivityInfo getReceiverInfo(in ComponentName className, int flags);
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    String getHello();
}

第二步：PackageManager类中增加抽象方法说明

public abstract class PackageManager {

    /**
     * This exception is thrown when a given package, application, or component
     * name can not be found.
     */
    public static class NameNotFoundException extends AndroidException {
        public NameNotFoundException() {
        }

        public NameNotFoundException(String name) {
            super(name);
        }
    }
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    /**
     * @hide
     */
    public abstract String getHello();
}

第三步：在PackageManagerService中增加getHello()方法的具体实现

public class PackageManagerService extends IPackageManager.Stub {
    static final String TAG = "PackageManager";
    static final boolean DEBUG_SETTINGS = false;
    private static final boolean DEBUG_PREFERRED = false;
    static final boolean DEBUG_UPGRADE = false;
    private static final boolean DEBUG_INSTALL = false;
    private static final boolean DEBUG_REMOVE = false;
    private static final boolean DEBUG_SHOW_INFO = false;
    private static final boolean DEBUG_PACKAGE_INFO = false;
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    public String getHello(){
        return "Hello,PMS";
    }
}

第四步：在ApplicationPackageManager中增加getHello()方法，具体实现为调用远程PackageManagerService的getHello()方法

final class ApplicationPackageManager extends PackageManager {
    private static final String TAG = "ApplicationPackageManager";
    private final static boolean DEBUG = false;
    private final static boolean DEBUG_ICONS = false;

    @Override
    public PackageInfo getPackageInfo(String packageName, int flags)
            throws NameNotFoundException {
        try {
            PackageInfo pi = mPM.getPackageInfo(packageName, flags);
            if (pi != null) {
                return pi;
            }
        } catch (RemoteException e) {
            throw new RuntimeException("Package manager has died", e);
        }

        throw new NameNotFoundException(packageName);
    }

    @Override
    public String[] currentToCanonicalPackageNames(String[] names) {
        try {
            return mPM.currentToCanonicalPackageNames(names);
        } catch (RemoteException e) {
            throw new RuntimeException("Package manager has died", e);
        }
    }
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        /**
     * @hide
     */
    @Override
	public String getHello() {
		// TODO Auto-generated method stub
		try {
			return mPM.isThirdParty(name);
		} catch (RemoteException e) {
			throw new RuntimeException("Package manager has died", e);
		}
	}
}

第五步：在MockPackageManager中增加getHello方法，文件在framework/base/test-runner/src

public class MockPackageManager extends PackageManager {

    @Override
    public PackageInfo getPackageInfo(String packageName, int flags)
    throws NameNotFoundException {
        throw new UnsupportedOperationException();
    }

    @Override
    public String[] currentToCanonicalPackageNames(String[] names) {
        throw new UnsupportedOperationException();
    }public class MockPackageManager extends PackageManager {

    @Override
    public PackageInfo getPackageInfo(String packageName, int flags)
    throws NameNotFoundException {
        throw new UnsupportedOperationException();
    }

    @Override
    public String[] currentToCanonicalPackageNames(String[] names) {
        throw new UnsupportedOperationException();
    }
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 /**
     * @hide
     */
	@Override
	public boolean getHello() {
		// TODO Auto-generated method stub
		throw new UnsupportedOperationException();
	}
}