Issue: Passing large data to second Activity

问题:

I've got an strange issue. I was looking around the web but didn't find an answer. I'm still a beginner in android programming. So let's go:

All I want to do is calling the second Activity with some data. It works fine with small data, but if the data gets large, the second Activity will not show and the first one finishes. Here's my code of the calling Method:

Intent intent = new Intent(ActivitySearch.this,ActivityResults.class);
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("data", searchList);
intent.putExtras(bundle);
startActivity(intent);

The part of receiving data is not important. Even if I don't try to read the bundle, the activity will not be called. I've tested this with following lines:

@Override
public void onCreate(Bundle savedInstanceState) {
Log.d("DEBUG","ActivityResult::onCreate()");
super.onCreate(savedInstanceState);

OnCreate() gets never called.

Maybe one of yours got an idea... Thank you for your help!

Edit:at least I forgot: This only happens under ICS. The app works like a charme with gingerbread and froyo.

Edit2: Logcat

10-10 14:49:46.951: D/OpenGLRenderer(21696): Flushing caches (mode 0)
10-10 14:49:47.011: V/ActivityThread(22429): com.example.amazonsearch white listed for hwui
10-10 14:49:50.821: W/IInputConnectionWrapper(21696): showStatusIcon on inactive InputConnection

回答1:

You are probably getting TransactionTooLargeException

As suggested by google android guide, you could use static fields or singletons to share data between activities.

They recommend it "For sharing complex non-persistent user-defined objects for short duration"

From your code it seems that's exactly what you need.

So your code in ActivitySearch.class could look something like this:

ActivityResults.data = searchList;
Intent intent = new Intent(ActivitySearch.this,ActivityResults.class);
startActivity(intent);

Then you can access ActivityResults.data from anywhere in ActivityResults activity after it starts.

For data that need to be shared between user sessions, it's not advisable to use static fields, since application process could be killed and restarted by android framework while app is running in background (if framework need to free resources). In such case all static fields will be reinitialized.

回答2:

The way I prefer passing large data is through using enums. Some advantages of this approach:

• No need to create singletons, you always have single instance of your enum;
• Data is properly encapsulated;
• Reference is deleted right after the activity receives it

Here is an example:

package com.jyvee.arguments;

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;

public class SomeActivity extends Activity {

    // Names for the arguments we pass to the
    // activity when we create it
    private final static String ARG_STRING = "ARG_STRING";
    private final static String ARG_INT = "ARG_INT";

    private String stringField;
    private int intField;
    private List<Object> arrayField;

    private enum DataHolder {
        INSTANCE;

        private List<Object> mObjectList;

        public static boolean hasData() {
            return INSTANCE.mObjectList != null;
        }

        public static void setData(final List<Object> objectList) {
            INSTANCE.mObjectList = objectList;
        }

        public static List<Object> getData() {
            final List<Object> retList = INSTANCE.mObjectList;
            INSTANCE.mObjectList = null;
            return retList;
        }
    }

    @Override
    protected void onCreate(final Bundle savedState) {
        super.onCreate(savedState);

        // Get the activity intent if there is a one
        final Intent intent = getIntent();

        // And retrieve arguments if there are any
        if (intent.hasExtra(ARG_STRING)) {
            stringField = intent.getExtras().getString(ARG_STRING);
        }
        if (intent.hasExtra(ARG_INT)) {
            intField = intent.getExtras().getInt(ARG_INT);
        }
        // And we retrieve large data from enum
        if (DataHolder.hasData()) {
            arrayField = DataHolder.getData();
        }

        // Now stringField, intField fields are available
        // within the class and can be accessed directly
    }

    /**
     * /** A static method for starting activity with supplied arguments
     * 
     * @param contextA
     *            context that starts this activity
     * @param stringArg
     *            A string argument to pass to the new activity
     * @param intArg
     *            An int argument to pass to the new activity
     * @param objectList
     *            An object list argument to pass to the new activity
     */
    public static void startActivity(final Context context, final String stringArg, 
            final int intArg, final List<Object> objectList) {

        // Initialize a new intent
        final Intent intent = new Intent(context, SomeActivity.class);

        // To speed things up :)
        intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);

        // And add arguments to the Intent
        intent.putExtra(ARG_STRING, stringArg);
        intent.putExtra(ARG_INT, intArg);

        // Now we put the large data into our enum instead of using Intent extras
        DataHolder.setData(objectList);

        context.startActivity(intent);
    }
}

More info here.

回答3:

If you pass a Large Information from one to other Activity then may be it make App Slower

but use Global Class to store variables with using that you can Easily Get or Set Any values

that declared in Global file

see this link :

http://androidresearch.wordpress.com/2012/03/22/defining-global-variables-in-android/

回答4:

As far as i remembered, up till API-8 (Froyo), there were some limitations (like 1MB) when passing parcelable objects through intents. However, you may simply write down your parcelable data into a file and send the file path to your next activity through bundle. Later, code your second activity to read the data from file and delete it afterwards.

回答5:

I have no idea why it doesn't work with large data, but if you don't find any way to fix it, I suggest you to use a custom global application, like here. (Also check the correct answer to make it works)