Question

我试图将活动A中的额外内容发送给B. 发送部分很好，变量不是空值，但我无法弄清楚如何在活动B中获取它们。这是发送代码：

    public void sendToFavorites(Context context){
        String vID,vThumbnail,vTitle;
        vID = sendResult.getId().getVideoId();
        vThumbnail = sendResult.getSnippet().getThumbnails().getMedium().getUrl();
        vTitle = sendResult.getSnippet().getTitle();
        Intent fav = new Intent(context,Favorites.class);
        fav.putExtra("title",vTitle);
        fav.putExtra("thumbnail",vThumbnail);
        fav.putExtra("id",vID);
}

这是获取代码：

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.favorites_layout);
    getSupportActionBar().setTitle("Favorites");
    initializeViews();
    //////////////////
    Bundle extras = getIntent().getExtras();
    vidID = extras.getString("id");
    vidTitle = extras.getString("title");
    vidThumbnail = extras.getString("thumbnail");
    loadFavorites();
}

我在这里开始活动B：

    @Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case R.id.favorites:
            intent = new Intent(this, Favorites.class);
            startActivity(intent);
    }
    return super.onOptionsItemSelected(item);
}

出于某种原因，当我使用NO log启动Activity B时，应用程序崩溃了..

我在做什么？

Answer 1

    public void sendToFavorites(Context context){
        String vID,vThumbnail,vTitle;
        vID = sendResult.getId().getVideoId();
        vThumbnail = sendResult.getSnippet().getThumbnails().getMedium().getUrl();
        vTitle = sendResult.getSnippet().getTitle();
        Intent fav = new Intent(context,Favorites.class);
        fav.putExtra("title",vTitle);
        fav.putExtra("thumbnail",vThumbnail);
        fav.putExtra("id",vID);
    }

您的Intent对象fav仅适用于此方法。由于您从未在此方法中调用startActivity(fav)，因此您开始Activity B时不会包含您的捆绑数据。有两种可能的替代方法 - 将fav声明为类变量并稍后引用它，如下所示：

public class MyClass extends ... {

Intent fav;
//...
    public void sendToFavorites(Context context){
        String vID,vThumbnail,vTitle;
        vID = sendResult.getId().getVideoId();
        vThumbnail = sendResult.getSnippet().getThumbnails().getMedium().getUrl();
        vTitle = sendResult.getSnippet().getTitle();
        fav = new Intent(context,Favorites.class);
        fav.putExtra("title",vTitle);
        fav.putExtra("thumbnail",vThumbnail);
        fav.putExtra("id",vID);
    }

//...later, during a button click....
    if (fav != null) {
       startActivity(fav);
    }

或者，正如我所希望的那样，将sendToFavourites()方法中的逻辑放在点击事件中：

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case R.id.favorites:
            String vID,vThumbnail,vTitle;
            vID = sendResult.getId().getVideoId();
            vThumbnail = sendResult.getSnippet().getThumbnails().getMedium().getUrl();
            vTitle = sendResult.getSnippet().getTitle();
            Intent fav = new Intent(context, Favorites.class); //Could use "this" instead of context if this class extends Activity
            fav.putExtra("title",vTitle);
            fav.putExtra("thumbnail",vThumbnail);
            fav.putExtra("id",vID);
            startActivity(fav);
    }
    return super.onOptionsItemSelected(item);
}

GetExtras无效

1 个答案: