How to do XOR with android studio

1, context description

Context is an interface to access global information, such as application resources (such as pictures, strings, etc. ), and some commonly used components inherit from the context, such as Activity and Service.

If you create a textView with Java code, the first setText () method of textView passes in a string directly, and the second setText () method passes in a plastic ID (hello_world under values \ \ strings.xml, namely:

[java] View Plain Text

Public class MainActivity extends ActionBarActivity {

Private TextView textView

@ Overlay

Protected void oncreate (bundle saved instancestate) (

super . oncreate(savedInstanceState)；

//setContentView(r . layout . activity _ main)；

textView = new textView(main activity . this)；

//textview . settext(" Hello geo storm ")；

textview . settext(r . string . hello _ world)；

SetContentView (text view);

}

In the above code, double-click the first setText () method and press F4 to see the constructor. The entry parameter is a string.

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public final void setText(char sequence text){

setText(text，mBufferType)；

}

Double-click the first setText () method and press F4 to view the constructor. The entry parameter is resid, its internal setText () is the first setText () method, and getContext () is MainActivity.this! ! !

[java] View Plain Text

public final void setText(int resid){

setText(getContext()。 getResources()。 getText(resid))；

}

After reading the constructor, we can also write according to the original text in the constructor:

[java] View Plain Text

//textview . settext(r . string . hello _ world)；

textview . settext(getApplicationContext()。 getResources()。 getText(r . string . hello _ world))；

Similarly, we can also access the picture resources:

[java] View Plain Text

Public class MainActivity extends ActionBarActivity {

Private TextView textView

Private ImageView imageView

@ Overlay

Protected void oncreate (bundle saved instancestate) (

super . oncreate(savedInstanceState)；

//setContentView(r . layout . activity _ main)；

//textView = new textView(main activity . this)；

//textview . settext(" Hello geo storm ")；

//textview . settext(r . string . hello _ world)；

//textview . settext(getApplicationContext()。 getResources()。 getText(r . string . hello _ world))；

ImageView = new imageview (this); //You can use this directly.

imageview . set image resource(r . MIP map . IC _ launcher)；

setContentView(imageView)；

}

2. Application and application description

Now we use context to share information between components. Create a App.java class to pass data, inherit from the application, add a string variable, and add a read-write constructor, as shown below:

[java] View Plain Text

Package com.example.lhb.context;

Import android.app.application;

Common class application extension application {

public String S = " DefaultString

Public empty set (string) (

S = s

}

Common string getS() {

Return to s;

}

Next, configure Android manifest: add Android: name = ". App "is added to the application, and another activity named Main2 is added. Add the same configuration as MainActivity in the configuration file, where

[java] View Plain Text

& lt？ Xml version =" 1.0 "encoding ="utf-8"? & gt

& lt listing xmlns: Android = "/apk/res/Android"

package = " com . example . lhb . context " & gt；

& lt application

android:name= "。 Application "

android:allowBackup="true "

Android:icon = " @ MIP map/IC _ launcher "

Android:label = " @ string/app _ name "

Android:theme = " @ style/app theme " & gt；

& lt activities

android:name= "。 Main activities "

Android:label = " main 1 " & gt；

& lt intention filter & gt

& ltaction Android:name = " Android . intent . action . main "/& gt；

& lt category Android: name = "android.intention.category.launcher"/>

& lt/intent-filter & gt；

& lt/activity & gt；

& lt activities

Android:name = " . main activity 2 activity "

Android:label = " main 2 " & gt；

& lt intention filter & gt

& ltaction Android:name = " Android . intent . action . main "/& gt；

& lt category Android: name = "android.intention.category.launcher"/>

& lt/intent-filter & gt；

& lt/activity & gt；

& lt/application & gt；

& lt/manifest & gt；

In Main 1, add the following code to Main2:

[java] View Plain Text

Package com.example.lhb.context;

Import android.support.v7.app.actionabaractivity;

Import android.os.bundle;

Import android.view.menu;

Import android.view.menuitem;

Import android.view.view;

Import android.widget.edittext;

Import android.widget.imageview;

Import android.widget.textview;

Public class MainActivity extends ActionBarActivity {

Private TextView textView

Private EditText editText

@ Overlay

Protected void oncreate (bundle saved instancestate) (

super . oncreate(savedInstanceState)；

setContentView(r . layout . activity _ main)；

textView =(textView)findViewById(r . id . textView)；

editText =(editText)findViewById(r . id . editText)；

//Read the default string

TextView.setText("*** Enjoy the data as follows: "+((app) getapplicationcontext ())). gets())；

findViewById(R.id.btnSave)。 SetOnClickListener (new view. OnClickListener() {

@ Overlay

Public void onClick (view v)

((App)getApplicationContext())。 setS(editText.getText()。 toString())；

Textview.settext (string.format ("* * * data is:% s", edittext.gettext (). tostring()))；

}

});

}

The effect is as follows:

3. Application life cycle

Override the constructor and execute it. It turns out that App.java's onCreate () function is executed before any active onCreate () function, which is very useful for our initialization.

[java] View Plain Text

Package com.example.lhb.context;

Import android.app.application;

Common class application extension application {

public String S = " DefaultString

Public empty set (string) (

S = s

}

Common string getS() {

Return to s;

}

@ Overlay