android开发中,判断是否安装了qq

Android系统中，判断应用有无安装有两种方式：
1.根据包名判断,以下为判断代码：
public boolean checkApkExist(Context context, String packageName) {
if (packageName == null || “”.equals(packageName))
return false;
try {
ApplicationInfo info = context.getPackageManager()
.getApplicationInfo(packageName,
PackageManager.GET_UNINSTALLED_PACKAGES);
return true;
} catch (NameNotFoundException e) {
return false;
}
}

2. 根据Intent判断，以下为判断代码：
public boolean checkApkExist(Context context, Intent intent) {
ListResolveInfo list = context.getPackageManager().queryIntentActivities(intent, 0);
if(list.size() 0){
return true;
}
return false;
}
public boolean checkApkExist(Context context, String packageName) {
if (packageName == null || “”.equals(packageName)) return false;
try {
ApplicationInfo info = context.getPackageManager() .getApplicationInfo(packageName, PackageManager.GET_UNINSTALLED_PACKAGES); return true;
} catch (NameNotFoundException e) { return false; }
}
public boolean checkApkExist(Context context, Intent intent) {
ListResolveInfo list = context.getPackageManager()
.queryIntentActivities(intent, 0);
if (list.size() 0) {
return true;
}
return false;
}

manifest.xml android:installLocation的值

因为你手机系统自带有一个QQ，没事的直接确定安装，或你把自带的那个删了，但手机必需root

没事，确定就行

通过反射得到ApplicationInfo源码中的installlocation这个Field，将你需要判断的appInfo传进去就OK了

manifest xmlns:android=http://schemas.android.com/apk/res/android
android:installLocation=preferExternal
...

installLocation有三个值可以选择：internalOnly、auto、preferExternal
选择preferExternal,系统会优先考虑将APK安装到SD卡上(当然最终用户可以选择为内部ROM存储上，如果SD存储已满，也会安装到内部存储上)

选择auto，系统将会根据存储空间自己去适应

选择internalOnly是指必须安装到内部才能运行

Android系统中，判断应用有无安装有两种方式：
1.根据包名判断,以下为判断代码：
public boolean checkApkExist(Context context, String packageName) {
if (packageName == null || “”.equals(packageName))
return false;
try {
ApplicationInfo info = context.getPackageManager()
.getApplicationInfo(packageName,
PackageManager.GET_UNINSTALLED_PACKAGES);
return true;
} catch (NameNotFoundException e) {
return false;
}
}
2. 根据Intent判断，以下为判断代码：
public boolean checkApkExist(Context context, Intent intent) {
ListResolveInfo list = context.getPackageManager().queryIntentActivities(intent, 0);
if(list.size() 0){
return true;
}
return false;
}
public boolean checkApkExist(Context context, String packageName) {
if (packageName == null || “”.equals(packageName)) return false;
try {
ApplicationInfo info = context.getPackageManager() .getApplicationInfo(packageName, PackageManager.GET_UNINSTALLED_PACKAGES); return true;
} catch (NameNotFoundException e) { return false; }
}
public boolean checkApkExist(Context context, Intent intent) {
ListResolveInfo list = context.getPackageManager()
.queryIntentActivities(intent, 0);
if (list.size() 0) {
return true;
}
return false;
}