onSaveInstanceState工作但未显示正确的结果

时间：2014-06-20 17:23:05

标签： android android-fragments

我试图让一个小应用程序练习片段间通信。每次单击左上角片段中的按钮时，基本片段中的计数器都会更新并显示点击次数。

我尝试使用onSaveInstanceState（）方法来保存数据，以便在旋转屏幕时，仍然可以正确显示累计的点击次数。通过使用Log，我已经看到在旋转期间保留了数据，但是，我不明白为什么即使我使用保留的数据设置TextView的内容，它也会恢复到状态，好像片段是首先创建。

这是我的代码：

package com.example.fragmenttrial;

    import android.os.Bundle;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentTransaction;
    import android.support.v7.app.ActionBarActivity;
    import android.util.Log;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.View.OnClickListener;

    public class MainActivity extends ActionBarActivity implements Communicator {

    private static final String DT = "Activity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.e(DT, "onCreate()");
        HelloFragment fragment1 = new HelloFragment();
        TrialFragment fragment2 = new TrialFragment();
        BaseFragment fragment3 = new BaseFragment();
        FragmentManager manager = getSupportFragmentManager();
        FragmentTransaction transaction = manager.beginTransaction();
        transaction.replace(R.id.hello_placeholder, fragment1, "myHelloFragment");
        transaction.replace(R.id.trial_placeholder, fragment2, "myTrialFragment");
        transaction.replace(R.id.base_placeholder, fragment3, "myBaseFragment");
        transaction.commit();
    }

    protected void onStart() {
        Log.e(DT,"onStart()");
        super.onStart();
    }

    protected void onPause() {
        Log.e(DT, "onPause()");
        super.onPause();
    }

    protected void onResume() {
        Log.e(DT, "onResume()");
        super.onResume();
    }

    protected void onRestart() {
        Log.e(DT, "onRestart()");
        super.onRestart();
    }

    protected void onStop() {
        Log.e(DT, "onStop()");
        super.onStop();
    }

    protected void onDestroy() {
        Log.e(DT, "onDestroy()");
        super.onDestroy();
    }

    protected void onSaveInstanceState(Bundle bundle) {
        Log.e(DT, "onSaveInstanceState()");
        super.onSaveInstanceState(bundle);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        Log.e(DT, "onCreateOptionsMenu()");
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        Log.e(DT, "onOptionsItemSelected");
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void respond(int times) {
        // TODO Auto-generated method stub
        BaseFragment fragment = (BaseFragment) getSupportFragmentManager().findFragmentById(R.id.base_placeholder);
        fragment.changeData(times);
        if(times == 10) {
            SimpleFragment mFrag = new SimpleFragment();
            FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
            trans.replace(R.id.trial_placeholder, mFrag);
            trans.commit();
        }

    }

}

activity_main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.fragmenttrial.MainActivity"
    tools:ignore="MergeRootFrame" 
    android:background="#0000FF">



    <LinearLayout 
        android:id="@+id/my_linear"
        android:layout_height="0dp"
        android:layout_width="fill_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <RelativeLayout 
            android:id="@+id/hello_placeholder"
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:background="#F2E0F7"
            />

        <RelativeLayout 
            android:id="@+id/trial_placeholder"
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:background="#FFFF00"

            />

     </LinearLayout>

    <RelativeLayout 
        android:id="@+id/base_placeholder"
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:background="#DF013A"
        />

</LinearLayout>

左上角片段（HelloFragment.java）

package com.example.fragmenttrial;

import javax.security.auth.login.LoginException;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class HelloFragment extends Fragment implements View.OnClickListener {

    private int times = 0;
    Communicator comm;
    public static final String FT = "Fragment";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.i(FT, "onCreateView()-hello");
        View v = inflater.inflate(R.layout.hello_frag, container, false);
        Button b = (Button) v.findViewById(R.id.button);
        b.setOnClickListener(this);
        return v;

    }

    public void onCreate(Bundle savedInstanceState) {
        Log.i(FT, "onCreate()-hello");
        super.onCreate(savedInstanceState);
        if(savedInstanceState == null) {
            //first time of creation
        } else {
            times = savedInstanceState.getInt("counter");
        }
    }

    public void onSaveInstanceState(Bundle outState) {
        Log.i(FT, "onSaveInstanceState()-hello");
        super.onSaveInstanceState(outState);
        outState.putInt("counter", times);
    }

    @Override
    public void onClick(View v) {
        times++;
        comm.respond(times);
    }

    public void onAttach(Activity activity) {
        Log.i(FT, "onAttach()-hello");
        super.onAttach(activity);
        comm = (Communicator) activity;
    }

    public void onActivityCreated(Bundle savedInstanceState) {
        Log.i(FT, "onActivityCreated()-hello");
        super.onActivityCreated(savedInstanceState);
    }

    public void onViewStateRestored(Bundle savedInstanceState) {
        Log.i(FT, "onViewStateRestored()-hello");
        super.onViewStateRestored(savedInstanceState);
    }

    public void onStart() {
        Log.i(FT, "onStart()-hello");
        super.onStart();
    }

    public void onResume() {
        Log.i(FT, "onResume()-hello");
        super.onResume();
    }

    public void onPause() {
        Log.i(FT, "onPause()-hello");
        super.onPause();
    }

    public void onStop() {
        Log.i(FT, "onStop()-hello");
        super.onStop();
    }

    public void onDestroy() {
        Log.i(FT, "onDestroy()-hello");
        super.onDestroy();
    }

    public void onDestroyView() {
        Log.i(FT, "onDestroyView()-hello");
        super.onDestroyView();
    }

    public void onDetach() {
        Log.i(FT,"onDetach()-hello");
        super.onDetach();
    }
}

hello_frag.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000000">    
    <Button 
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="#DA81F5"
        android:text="Hello world!"
        android:textColor="#ffffff"
        android:onClick="onClick"/>

</RelativeLayout>

BaseFragment.java 

package com.example.fragmenttrial;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class BaseFragment extends Fragment {

    int counter;
    TextView textView;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.i(HelloFragment.FT, "onCreateView()-Base");

        View v = inflater.inflate(R.layout.base_frag, container, false);
        textView = (TextView) v.findViewById(R.id.text);

        if(savedInstanceState == null) {
            //first time being created
        } else {
            counter = savedInstanceState.getInt("counter"); 
            System.out.println(counter);
            textView.setText("Button was clicked: " + counter + " times.");
            System.out.println(textView.getText().toString());
        }

        return v;
    }

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    } 

    public void changeData(int data) {
        counter = data;
        textView.setText("Button was clicked: " + data + " times.");
    }

    public void onSaveInstanceState(Bundle outState) {
        Log.i(HelloFragment.FT,"onSaveInstanceState()-Base");
        super.onSaveInstanceState(outState);
        outState.putInt("counter", counter);
    }
}

base_frag.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:background="#0B4C5F">

    <TextView 
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Number of clicks:  "
        android:textColor="#000000"
        android:background="@android:color/transparent"/>

</RelativeLayout>

旋转后的日志猫：

06-20 12:03:10.929: E/Activity(7185): onPause()
06-20 12:03:10.929: I/Fragment(7185): onPause()-hello
06-20 12:03:10.929: E/Activity(7185): onSaveInstanceState()
06-20 12:03:10.976: I/Fragment(7185): onSaveInstanceState()-hello
06-20 12:03:10.980: I/Fragment(7185): onSaveInstanceState()-Base
06-20 12:03:10.984: E/Activity(7185): onStop()
06-20 12:03:10.984: I/Fragment(7185): onStop()-hello
06-20 12:03:10.984: E/Activity(7185): onDestroy()
06-20 12:03:10.984: I/Fragment(7185): onDestroyView()-hello
06-20 12:03:10.988: I/Fragment(7185): onDestroy()-hello
06-20 12:03:10.988: I/Fragment(7185): onDetach()-hello
06-20 12:03:11.113: I/Fragment(7185): onAttach()-hello
06-20 12:03:11.113: I/Fragment(7185): onCreate()-hello
06-20 12:03:11.207: E/Activity(7185): onCreate()
06-20 12:03:11.211: E/Activity(7185): onStart()
06-20 12:03:11.211: I/Fragment(7185): onCreateView()-hello
06-20 12:03:11.218: I/Fragment(7185): onActivityCreated()-hello
06-20 12:03:11.218: I/Fragment(7185): onViewStateRestored()-hello
06-20 12:03:11.242: I/Fragment(7185): onCreateView()-Base
06-20 12:03:11.250: D/dalvikvm(7185): GC_CONCURRENT freed 153K, 3% free 8277K/8519K, paused 30ms+22ms, total 101ms
06-20 12:03:11.254: I/System.out(7185): 3
06-20 12:03:11.254: I/System.out(7185): Button was clicked: 3 times.
06-20 12:03:11.254: I/Fragment(7185): onDestroyView()-hello
06-20 12:03:11.254: I/Fragment(7185): onDestroy()-hello
06-20 12:03:11.254: I/Fragment(7185): onDetach()-hello
06-20 12:03:11.257: I/Fragment(7185): onAttach()-hello
06-20 12:03:11.257: I/Fragment(7185): onCreate()-hello
06-20 12:03:11.257: I/Fragment(7185): onCreateView()-hello
06-20 12:03:11.261: I/Fragment(7185): onActivityCreated()-hello
06-20 12:03:11.261: I/Fragment(7185): onViewStateRestored()-hello
06-20 12:03:11.261: I/Fragment(7185): onCreateView()-Base
06-20 12:03:11.269: I/Fragment(7185): onStart()-hello
06-20 12:03:11.269: E/Activity(7185): onCreateOptionsMenu()
06-20 12:03:11.273: E/Activity(7185): onResume()
06-20 12:03:11.273: I/Fragment(7185): onResume()-hello

可以看到，textview文本字段在中间被更改了。但是，当显示时，它会更改回初始状态“点击次数：”，如XML中所定义。

0 个答案:

没有答案
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