非 Activity 中的 SharedPreferences

Question

您好，我需要从一个 Activity 到另一个 Class 获取一个字符串。我需要 Test2 class 中的字符串 VideoID。我想使用 sharedpreferences，但这不起作用。我如何在这里使用 sharedpreferences？或者我如何获得字符串的任何其他想法？谢谢

在我的 Activity 我有这个按钮：

// Video Button
final Button videobutton = (Button) findViewById(R.id.videobutton);
videobutton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            // Video ID save
            SharedPreferences.Editor editor = getSharedPreferences("VideoID_saver", MODE_PRIVATE).edit();
            editor.putString("VideoID", current_video);
            editor.commit();

            Intent OpenTest = new Intent(Questions.this, Test2.class);
            startActivity(OpenTest);
        }
    });

Test2.class 看起来像这样：

import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.youtube.player.YouTubeBaseActivity;
import com.google.android.youtube.player.YouTubeInitializationResult;
import com.google.android.youtube.player.YouTubePlayer;
import com.google.android.youtube.player.YouTubePlayer.ErrorReason;
import com.google.android.youtube.player.YouTubePlayer.PlaybackEventListener;
import com.google.android.youtube.player.YouTubePlayer.PlayerStateChangeListener;
import com.google.android.youtube.player.YouTubePlayer.Provider;
import com.google.android.youtube.player.YouTubePlayerView;

public class Test2 extends YouTubeBaseActivity implements YouTubePlayer.OnInitializedListener {
    public static final String API_KEY = "AIzaSyCb2pCHbqhBDKaYzFvU7g1SBG14YrM3XWE";

    //Test
    SharedPreferences prefs = getSharedPreferences("VideoID_saver", MODE_PRIVATE);
    String testtext = prefs.getString("VideoID", "");

    //http://youtu.be/<VIDEO_ID>
    public final String VIDEO_ID = testtext;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test2);

        /** Initializing YouTube player view **/
        YouTubePlayerView youTubePlayerView = (YouTubePlayerView) findViewById(R.id.youtube_player);
        youTubePlayerView.initialize(API_KEY, this);
    }

    @Override
    public void onInitializationFailure(Provider provider, YouTubeInitializationResult result) {
        Toast.makeText(this, "Failured to Initialize!", Toast.LENGTH_LONG).show();
    }

    @Override
    public void onInitializationSuccess(Provider provider, YouTubePlayer player, boolean wasRestored) {
        /** add listeners to YouTubePlayer instance **/
        player.setPlayerStateChangeListener(playerStateChangeListener);
        player.setPlaybackEventListener(playbackEventListener);

        /** Start buffering **/
        if (!wasRestored) {
            player.cueVideo(VIDEO_ID);
        }
    }

    private PlaybackEventListener playbackEventListener = new PlaybackEventListener() {

        @Override
        public void onBuffering(boolean arg0) {}

        @Override
        public void onPaused() {}

        @Override
        public void onPlaying() {}

        @Override
        public void onSeekTo(int arg0) {}

        @Override
        public void onStopped() {}

    };

    private PlayerStateChangeListener playerStateChangeListener = new PlayerStateChangeListener() {

        @Override
        public void onAdStarted() {}

        @Override
        public void onError(ErrorReason arg0) {}
 
        @Override
        public void onLoaded(String arg0) {}

        @Override
        public void onLoading() {}

        @Override
        public void onVideoEnded() {}

        @Override
        public void onVideoStarted() {}
    };

Answer 1

您可能以某种方式访问了不同的 SharedPreferences 实例。使用 getDefaultSharedPreferences() 方法更容易确保不会发生这种情况：

在你身上Activity:

PreferenceManager.getDefaultSharedPreferences(this)
    .edit()
    .putString("VideoID", current_video)
    .apply();

在您的 Test2 onCreate 方法中：

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String testtext = prefs.getString("VideoID", "");

Answer 2

两件事。 Test2 似乎继承了一个 activity，所以不确定为什么你的标题说 Non-Activity。 SharedPreferences 读写似乎没问题，但也许在 activity 上的构造函数更改为运行之前读取 sharedpreferences 还为时过早。

Answer 3

您的目标是从按钮获取一个字符串到 test2. 似乎最好完全避免共享首选项并通过 [=20] 直接将字符串传递给下一个 activity =]函数。

像这样：

Intent OpenTest = new Intent(Questions.this, Test2.class);
i.putExtra("VideoID", current_video);
startActivity(OpenTest);

然后在 OnCreate 方法中从新的 activity 中提取它：

//http://youtu.be/<VIDEO_ID>
public final String VIDEO_ID;

@
Override
protected void onCreate(Bundle savedInstanceState) {

//Test
Intent intent = getIntent();
VIDEO_ID = intent.getExtras().getString("VideoID");

}

非 Activity 中的 SharedPreferences

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