Transfer data from one Activity to Another Activit

问题:

I would like to be able to transfer data from one activity to another activity. How can this be done?

回答1:

Through the below code we can send the values between activities

use the below code in parent activity

Intent myintent=new Intent(Info.this, GraphDiag.class).putExtra("<StringName>", value);
startActivity(myintent);

use the below code in child activity

String s= getIntent().getStringExtra(<StringName>);

回答2:

There are couple of ways by which you can access variables or object in other classes or Activity.

A. Database

B. shared preferences.

C. Object serialization.

D. A class which can hold common data can be named as Common Utilities it depends on you.

E. Passing data through Intents and Parcelable Interface.

It depend upon your project needs.

A. Database

SQLite is an Open Source Database which is embedded into Android. SQLite supports standard relational database features like SQL syntax, transactions and prepared statements.

Tutorials -- http://www.vogella.com/articles/AndroidSQLite/article.html

B. Shared Preferences

Suppose you want to store username. So there will be now two thing a Key Username, Value Value.

How to store

 // Create object of SharedPreferences.
 SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
 //now get Editor
 SharedPreferences.Editor editor = sharedPref.edit();
 //put your value
 editor.putString("userName", "stackoverlow");

 //commits your edits
 editor.commit();

Using putString(),putBoolean(),putInt(),putFloat(),putLong() you can save your desired dtatype.

How to fetch

SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
String userName = sharedPref.getString("userName", "Not Available");

http://developer.android.com/reference/android/content/SharedPreferences.html

C. Object Serialization

Object serlization is used if we want to save an object state to send it over network or you can use it for your purpose also.

Use java beans and store in it as one of his fields and use getters and setter for that

JavaBeans are Java classes that have properties. Think of properties as private instance variables. Since they're private, the only way they can be accessed from outside of their class is through methods in the class. The methods that change a property's value are called setter methods, and the methods that retrieve a property's value are called getter methods.

public class VariableStorage implements Serializable  {

    private String inString ;

    public String getInString() {
        return inString;
    }

    public void setInString(String inString) {
        this.inString = inString;
    }


}

Set the variable in you mail method by using

VariableStorage variableStorage = new VariableStorage();
variableStorage.setInString(inString);

Then use object Serialzation to serialize this object and in your other class deserialize this object.

In serialization an object can be represented as a sequence of bytes that includes the object's data as well as information about the object's type and the types of data stored in the object.

After a serialized object has been written into a file, it can be read from the file and deserialized that is, the type information and bytes that represent the object and its data can be used to recreate the object in memory.

If you want tutorial for this refer this link

http://javawithswaranga.blogspot.in/2011/08/serialization-in-java.html

Get variable in other classes

D. CommonUtilities

You can make a class by your self which can contain common data which you frequently need in your project.

Sample

public class CommonUtilities {

    public static String className = "CommonUtilities";

}

E. Passing Data through Intents

Please refer this tutorial for this option of passing data.

http://shri.blog.kraya.co.uk/2010/04/26/android-parcel-data-to-pass-between-activities-using-parcelable-classes/

回答3:

When you passing data from one activity to another activity perform like this

In Parent activity:

startActivity(new Intent(presentActivity.this, NextActivity.class).putExtra("KEY_StringName",ValueData)); 

or like shown below in Parent activity

Intent intent  = new Intent(presentActivity.this,NextActivity.class);     
intent.putExtra("KEY_StringName", name);   
intent.putExtra("KEY_StringName1", name1);   
startActivity(intent);

In child Activity perform as shown below

TextView tv = ((TextView)findViewById(R.id.textViewID))
tv.setText(getIntent().getStringExtra("KEY_StringName"));

or do like shown below in child Activity

TextView tv = ((TextView)findViewById(R.id.textViewID));
TextView tv1 = ((TextView)findViewById(R.id.textViewID1))

/* Get values from Intent */
Intent intent = getIntent();         
String name  = intent.getStringExtra("KEY_StringName");
String name1  = intent.getStringExtra("KEY_StringName1");

tv.setText(name);
tv.setText(name1);

回答4:

Passing data from one activity to other in android

Intent intent = new Intent(context, YourActivityClass.class);
intent.putExtra(KEY, <your value here>);

startActivity(intent);

Retrieving bundle data from android activity

Intent intent = getIntent();
  if (intent!=null) {
  String stringData= intent.getStringExtra(KEY);
  int numberData = intent.getIntExtra(KEY, defaultValue);
  boolean booleanData = intent.getBooleanExtra(KEY, defaultValue);
  char charData = intent.getCharExtra(KEY, defaultValue);   }

回答5:

Hopefully you will find the answer from here Send Data to Another Activity - Simple Android Login

回答6:

You just have to send extras while calling your intent

like this:

Intent intent = new Intent(getApplicationContext(), SecondActivity.class); intent.putExtra("Variable Name","Value you want to pass"); startActivity(intent);

Now on the OnCreate method of your SecondActivity you can fetch the extras like this

If the value u sent was in "long"

long value = getIntent().getLongExtra("Variable Name which you sent as an extra", defaultValue(you can give it anything));

If the value u sent was a "String"

String value = getIntent().getStringExtra("Variable Name which you sent as an extra");

If the value u sent was a "Boolean"

Boolean value = getIntent().getStringExtra("Variable Name which you sent as an extra",defaultValue);

回答7:

Your Purpose

Suppose You want to Go From Activity A to Activity B.

So We Use an Intent to switch activity

the typical code Looks Like this -

In Activity A [A.class]

//// Create a New Intent object
Intent i = new Intent(getApplicationContext(), B.class);

/// add what you want to pass from activity A to Activity B
i.putExtra("key", "value");

/// start the intent
startActivity(i);

In Activity B [B.class]

And to Get the Data From the Child Activity

Intent i = getIntent();

if (i!=null) {
   String stringData= i.getStringExtra("key");
}

回答8:

This works best:

Through the below code we can send the values between activities

use the below code in parent activity(PARENT CLASS/ VALUE SENDING CLASS)

Intent myintent=new Intent(<PARENTCLASSNAMEHERE>.this,<TARGETCLASSNAMEHERE>.class).putExtra("<StringName>", value);
startActivity(myintent);

use the below code in child activity(TARGET CLASS/ACTIVITY)

String s= getIntent().getStringExtra(<StringName>);

Please see here that "StringName" is the name that the destination/child activity catches while "value" is the variable name, same as in parent/target/sending class.