PackageInstaller作为安装应用的应用，在Android中的地位有些特殊。
看看在AndroidManifest.xml中的声明：
<activity android:name=".PackageInstallerActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:excludeFromRecents="true">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<action android:name="android.intent.action.INSTALL_PACKAGE" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="content" />
<data android:scheme="file" />
<data android:mimeType="application/vnd.android.package-archive" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.INSTALL_PACKAGE" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="file" />
<data android:scheme="package" />
</intent-filter>
</activity>可以看到对application/vnd.android.package-archive这个mime的处理，还有android.intent.action.INSTALL_PACKAGE这个action的处理。
在文件管理器中点击apk文件，或者发送以上intent-filter中对应的action，就会调用PackageInstaller。
1.只安装指定前缀包名的应用
我们可以在initiateInstall()这个函数中，通过包名对将要安装的应用进行管控，参考代码如下：
private void initiateInstall() {
String pkgName = mPkgInfo.packageName;
Log.v("AZ","[initiateInstall]pkgName:" + pkgName);
if(pkgName.startsWith("com.zms")){
// Check if there is already a package on the device with this name
// but it has been renamed to something else.
String[] oldName = mPm.canonicalToCurrentPackageNames(new String[] { pkgName });
if (oldName != null && oldName.length > 0 && oldName[0] != null) {
pkgName = oldName[0];
mPkgInfo.packageName = pkgName;
mPkgInfo.applicationInfo.packageName = pkgName;
}
// Check if package is already installed. display confirmation dialog if replacing pkg
try {
// This is a little convoluted because we want to get all uninstalled
// apps, but this may include apps with just data, and if it is just
// data we still want to count it as "installed".
mAppInfo = mPm.getApplicationInfo(pkgName,
PackageManager.GET_UNINSTALLED_PACKAGES);
if ((mAppInfo.flags&ApplicationInfo.FLAG_INSTALLED) == 0) {
mAppInfo = null;
}
} catch (NameNotFoundException e) {
mAppInfo = null;
}
mInstallFlowAnalytics.setReplace(mAppInfo != null);
mInstallFlowAnalytics.setSystemApp(
(mAppInfo != null) && ((mAppInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0));
startInstallConfirm();
}else{
finish();
}
}以上代码的效果就是，只安装包名以“com.zms”开头的应用。其他的不会出现安装界面，直接finish()。
2.PackageInstaller安装完某个应用，自动打开：
packages/apps/PackageInstaller/src/com/android/packageinstaller/InstallAppProgress.java
private Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case INSTALL_COMPLETE:
mInstallFlowAnalytics.setFlowFinishedWithPackageManagerResult(msg.arg1);
if (getIntent().getBooleanExtra(Intent.EXTRA_RETURN_RESULT, false)) {
Intent result = new Intent();
result.putExtra(Intent.EXTRA_INSTALL_RESULT, msg.arg1);
setResult(msg.arg1 == PackageManager.INSTALL_SUCCEEDED
? Activity.RESULT_OK : Activity.RESULT_FIRST_USER,
result);
finish();
return;
}
// Update the status text
mProgressBar.setVisibility(View.INVISIBLE);
// Show the ok button
int centerTextLabel;
int centerExplanationLabel = -1;
LevelListDrawable centerTextDrawable = (LevelListDrawable) getResources()
.getDrawable(R.drawable.ic_result_status);
if (msg.arg1 == PackageManager.INSTALL_SUCCEEDED) {
mLaunchButton.setVisibility(View.VISIBLE);
centerTextDrawable.setLevel(0);
centerTextLabel = R.string.install_done;
// Enable or disable launch button
mLaunchIntent = getPackageManager().getLaunchIntentForPackage(
mAppInfo.packageName);
boolean enabled = false;
if(mLaunchIntent != null) {
List<ResolveInfo> list = getPackageManager().
queryIntentActivities(mLaunchIntent, 0);
if (list != null && list.size() > 0) {
enabled = true;
}
if (enabled) {
// ZMS:Add for opening app automatically START
if(mAppInfo.packageName.equals("com.zms.demo")){
startActivity(mLaunchIntent);
}
// ZMS:END
mLaunchButton.setOnClickListener(InstallAppProgress.this);
} else {
mLaunchButton.setEnabled(false);
}
} else if (msg.arg1 == PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE){
/// M: [ALPS00269830][ICS-TDD][Symbio][Free test] Assertion while playing music when downloading apks @{
if (!isFinishing()) {
Log.d(TAG, "!isFinishing()"); // Check to see whether this activity is in the process of finishing
showDialogInner(DLG_OUT_OF_SPACE);
}
/// @}
return;
} else {
// Generic error handling for all other error codes.
centerTextDrawable.setLevel(1);
centerExplanationLabel = getExplanationFromErrorCode(msg.arg1);
centerTextLabel = R.string.install_failed;
mLaunchButton.setVisibility(View.INVISIBLE);
}
if (centerTextDrawable != null) {
centerTextDrawable.setBounds(0, 0,
centerTextDrawable.getIntrinsicWidth(),
centerTextDrawable.getIntrinsicHeight());
mStatusTextView.setCompoundDrawablesRelative(centerTextDrawable, null,
null, null);
}
mStatusTextView.setText(centerTextLabel);
if (centerExplanationLabel != -1) {
mExplanationTextView.setText(centerExplanationLabel);
mExplanationTextView.setVisibility(View.VISIBLE);
} else {
mExplanationTextView.setVisibility(View.GONE);
}
mDoneButton.setOnClickListener(InstallAppProgress.this);
mOkPanel.setVisibility(View.VISIBLE);
break;
default:
break;
}
}
};