android studio Failure [INSTALL_PARSE_FAILED_MANIFEST_MALFORMED]

First,when i found this problem when i ran my application with Android Studio.

Then,i clicked "OK".But i failed  in installing my application .

So i tried to solve the problem in five ways 

1.

First  i uninstalled the application on my phone , delete the apk in my computer and  click build- clean project in Android Studio , and ran the project again .And there's no use .

2.

then i searched that on the Internet .And i found this 

https://stackoverflow.com/questions/26721951/install-parse-failed-manifest-malformed

So,the first person in it said that it is because the package name cannot have capital letters.

But my package name is 

package="doge.healthcare"

So,it does'nt work .

3. Another one said that it maybe the prolem of MIUI system, so i disable the function as he said and roboot my phone , no thing changed .

4. And  another one said that it  worked after change this in Android Studio .But it doesn't work .....

5.Okay , at last i find the problem 

    android:taskAffinity="String"

it should be changed by 

    android:taskAffinity=".string"
Okay......So careless...