Question

这是我的活动：

    public class HomeTimelineActivity extends AppCompatActivity {
    private TwitterClient client;
    Context mContext;
    @BindView(R.id.rvTweets)
    RecyclerView rvTweets;
    List<Tweet> mTweets;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home_timeline);
Butterknife.bind(this);
        client = TwitterApplication.getRestClient();
        populateTimeline();
    }

    private void populateTimeline() {
        client.getHomeTimeline(new JsonHttpResponseHandler() {
            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONArray jsonArray) {
                Log.d("DEBUG", jsonArray.toString());

                mTweets = new ArrayList<Tweet>();

                    for (int i = 0; i < jsonArray.length(); i++) {
                        try {
                            JSONObject jsonTweet = jsonArray.getJSONObject(i);
                            Tweet tweet = new Tweet();
                            tweet.setBody(jsonTweet.getString("text"));
                            tweet.setUid(jsonTweet.getLong("id"));
                            tweet.setCreateAt(jsonTweet.getString("created_at"));
                            JSONObject jsonUser = jsonTweet.getJSONObject("user");
                            User user = new User();
                            user.setName(jsonUser.getString("name"));
                            user.setUid(jsonUser.getLong("id"));
                            user.setScreenname(jsonUser.getString("screen_name"));
                            user.setProfileImageurl(jsonUser.getString("profile_image_url"));
                            tweet.setUser(user);

                            mTweets.add(tweet);

                            runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    TweetAdapter adapter = new TweetAdapter(mContext, mTweets);
                                    rvTweets.setAdapter(adapter);

                                    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(mContext);
                                    rvTweets.setLayoutManager(layoutManager);

                                }
                            });


            } catch (JSONException e) {
                e.printStackTrace();
                continue;
            }
        }

    }


            @Override
            public void onFailure(int statusCode, Header[] headers, Throwable throwable, JSONArray errorResponse) {
                Log.d("DEBUT", errorResponse.toString());
            }
        });
    }
}

这是我的适配器：

public class TweetAdapter extends RecyclerView.Adapter<TweetAdapter.TweetViewHolder>{
    private Context mContext;
    private List<Tweet> mTweets;

    // Automatically add the Constructor here

    public TweetAdapter(Context context, List<Tweet> tweets) {
        mContext = context;
        mTweets = tweets;
    }


    // Implements compulsory methods

    @Override
    public TweetViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.tweet_list_items,
                parent, false);
        TweetViewHolder viewHolder = new TweetViewHolder(view);

        return viewHolder;
    }


    @Override
    public void onBindViewHolder(TweetViewHolder holder, int position) {
        holder.bindModel(mTweets.get(position));
    }

    @Override
    public int getItemCount() {
        return mTweets.size();
    }

    public class TweetViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        // Hook the ID to new created Widget using ButterKnife
        @BindView(R.id.imgUserProfile)
        ImageView userProfile;
        @BindView(R.id.tvUserName)
        TextView userName;
        @BindView(R.id.tvTweet)
        TextView tweetText;

        TweetViewHolder(View view) {
            super(view);
            ButterKnife.bind(this, view);

            // Set the OnclickListener of an item in list
            itemView.setOnClickListener(this);
        }


        void bindModel(Tweet tweet) {
            // Use the Widget mVar and the model name to set_get info
            tweetText.setText(tweet.getBody());
        }

        @Override
        public void onClick(View view) {
            // Add What happen with OnClick


        }
    }

}

我尝试使用mTweets List设置适配器。我使用调试器来确保getTweet方法返回了足够的Object tweets = {ArrayList @ 5524} size = 25

0 = {Tweet@5530} 
 1 = {Tweet@5531} 
 2 = {Tweet@5532} 
 3 = {Tweet@5533} 
 4 = {Tweet@5534} 
 5 = {Tweet@5535} 
 6 = {Tweet@5536} 
 7 = {Tweet@5537} 
 8 = {Tweet@5538} 
 9 = {Tweet@5539} 
 10 = {Tweet@5540} 
 11 = {Tweet@5541}

但是，当我尝试设置适配器时，没有显示数据，应用程序立即停止。奇怪的是，Logcat是空白的，没有任何信息。它只是黑色。 Twitter的身份验证工作正常。有人请帮帮我。

Answer 1

您需要遵循一些步骤来提高代码性能并使其正常运行。

您缺少的主要是您在循环中的每次迭代后设置mTweets。只有在填充整个列表后，才应在适配器中设置mTweets。接下来，您应该调用适配器 notifyDataSetChanged（）。

请遵循以下：

第1步

 // Class variable adapter...
 private TweetAdapter adapter;

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

        client = TwitterApplication.getRestClient();

        // Initially pass null as the mTweets since you don't have any tweets right now...
        adapter = new TweetAdapter(mContext, null);
        rvTweets.setAdapter(adapter);

        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(mContext);

        rvTweets.setLayoutManager(layoutManager);
        populateTimeline();
    }

第2步 在TweetAdapter中，修改getItemCount方法以处理mTweets上的空检查。将新方法addNewTweets添加到适配器。

   @Override
    public int getItemCount() {
        return (mTweets !=null) ? mTweets.size() : 0;
    }

    public void setNewTweets(List<Tweet> newTweetList) {
        this.mTweets = newTweetList;
    }

第3步 修改此方法populateTimeline

private void populateTimeline() {
        client.getHomeTimeline(new JsonHttpResponseHandler() {
            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONArray jsonArray) {
                Log.d("DEBUG", jsonArray.toString());

                mTweets = new ArrayList<Tweet>();

                    for (int i = 0; i < jsonArray.length(); i++) {
                        try {
                            JSONObject jsonTweet = jsonArray.getJSONObject(i);
                            Tweet tweet = new Tweet();
                            tweet.setBody(jsonTweet.getString("text"));
                            tweet.setUid(jsonTweet.getLong("id"));
                            tweet.setCreateAt(jsonTweet.getString("created_at"));
                            JSONObject jsonUser = jsonTweet.getJSONObject("user");
                            User user = new User();
                            user.setName(jsonUser.getString("name"));
                            user.setUid(jsonUser.getLong("id"));
                            user.setScreenname(jsonUser.getString("screen_name"));
                            user.setProfileImageurl(jsonUser.getString("profile_image_url"));
                            tweet.setUser(user);

                            mTweets.add(tweet);


    /*  REMOVE THIS CODE!    
                                    runOnUiThread(new Runnable() {
                                        @Override
                                        public void run() {
                                            TweetAdapter adapter = new TweetAdapter(mContext, mTweets);
                                            rvTweets.setAdapter(adapter);

                                            RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(mContext);
                                            rvTweets.setLayoutManager(layoutManager);

                                        }
                                    });
        */

            } catch (JSONException e) {
                e.printStackTrace();
                continue;
            }

           // NOW SET MTWEETS IN YOUR ADAPTER.
           // NOTIFY the adapter that the data is changed.

           adapter.setNewTweets(mTweets);
           adapter.notifyDataSetChanged();

        }

    }

setAdapter时，ArrayList为零

1 个答案: