ListView中利用另一方法AdapterView.setOnItemClickListener来设置列表项的点击事件监听器

Dear 丶 2023-08-17 17:12 16阅读 0赞

**对比之间在自定义适配器中设置列表项点击事件监听器的方法, 这里说明第二种方法, 这种办法相对更好,更省内存资源**

同是Miwok项目, 举个例子, 在NumbersActivity中可以用一种方法设置列表项的点击事件监听器, 之间在NumbersActivity中利用listView.setOnItemClickListener()设置;

另外注意: 在播放完后, 一旦该MediaPlayer对象再被使用,应该调用release()方法将这些资源释放.

public class NumbersActivity extends AppCompatActivity { 
    
        MediaPlayer mediaPlayer;
    
        //This listener gets triggered when the {@link MediaPlayer} has completed
        //playing the audio files.
        private MediaPlayer.OnCompletionListener completionListener = new MediaPlayer.OnCompletionListener(){ 
            public void onCompletion(MediaPlayer mediaPlayer){ 
                //Toast.makeText(NumbersActivity.this, "I'm done" , Toast.LENGTH_SHORT).show();
                //Now that the sound file has finished playing, release the media player resources.
                releaseMediaPlayer();
            }
        };
    
        @Override
        protected void onCreate(Bundle savedInstanceState) { 
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_numbers);
    
            //create a list of Word
            final ArrayList<Word> words = new ArrayList<Word>();
    
            words.add(new Word("lutti", "one", R.drawable.number_one, R.raw.number_one));
            words.add(new Word("otiiko", "two", R.drawable.number_two,R.raw.number_two));
            words.add(new Word("tolookosu", "three", R.drawable.number_three, R.raw.number_three));
            words.add(new Word("oyyisa", "four", R.drawable.number_four, R.raw.number_four));
            words.add(new Word("massokka", "five", R.drawable.number_five, R.raw.number_five));
            words.add(new Word("temmokka", "six", R.drawable.number_six, R.raw.number_six));
            words.add(new Word("kenekaku", "seven", R.drawable.number_seven, R.raw.number_seven));
            words.add(new Word("kawinta", "eight", R.drawable.number_eight, R.raw.number_eight));
            words.add(new Word("wo'e", "nine", R.drawable.number_nine, R.raw.number_nine));
            words.add(new Word("na'aacha", "ten", R.drawable.number_ten, R.raw.number_ten));
    
            WordAdapter wordAdapter = new WordAdapter(this, words);
            ListView listView  = (ListView)findViewById(R.id.numbers_list);
            listView.setAdapter(wordAdapter);
    
    
    
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){ 
                @Override
                //AdapterView: the AdapterView where the Click happened.
                //view: the view within the AdapterView that was clicked(this will be view provided by the adapter).
                //position: the position of the view int the adapter.
                //id: the row id of the item that was clicked.
                public void onItemClick(AdapterView<?> AdapterView, View view, int position, long id) { 
                    //Release the media player if it currently exists because we are about to
                    //play a different sound file.
                    releaseMediaPlayer();
                    Word currentWord = words.get(position);
                    mediaPlayer = MediaPlayer.create(view.getContext(), currentWord.getAudioResourceId());
                    mediaPlayer.start();
                    //Setup a listener on the media player, so that we can stop and release the
                    //media player once the sounds has finished playing.
                    mediaPlayer.setOnCompletionListener(completionListener);
                }
            });
        }
    
        /** * Clean up the media player by releasing its resources. */
        private void releaseMediaPlayer(){ 
            //If the media player is not null, the it may be currently playing a sound.
            if(mediaPlayer != null){ 
                //Regardless of the current state of the media, release its resources.
                //because wo no longer need it.
                mediaPlayer.release();
    
                //Set the mediaPlayer back to null.For our code, we've decided that
                //setting the media player to null is an easy way to tell that the media player
                //is not configured to play an audio file at the moment.
                mediaPlayer = null;
            }
        }
    }

注意:ListView 和GridView 同是AdapterView的子类  
删除第一种设置列表项点击事件监听器的方法, 即在适配器中设置点击事件监听器

public class WordAdapter extends ArrayAdapter<Word> { 
    
        /** * This is our own custom constructor (it doesn't mirror a superclass constructor). * The context is used to inflate the layout file, and the list is the data we want * to populate into the lists. * * @param context The current context. Used to inflate the layout file. * @param words A List of word objects to display in a list */
        public WordAdapter(Activity context, ArrayList<Word> words){ 
            super(context, 0, words);
        }
    
        /** * Provides a view for an AdapterView (ListView, GridView, etc.) * * @param position The position in the list of data that should be displayed in the list item view. * @param convertView The recycled view to populate. * @param parent The parent ViewGroup that is used for inflation. * @return The View for the position in the AdapterView. */
        @NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { 
            //return super.getView(position, convertView, parent);
    
            // Check if the existing view is being reuse,otherwise inflate the view
            // (if convertView is null,there is no view to reuse, In this case we will need to inflate
            // one from the list item layout from scratch)
            View listItemView = convertView;
            if(listItemView == null){ 
                //LayoutInflater is an abstract class,and have no static method :inflate(),so
                //we should use LayoutInflater.from(getContext()) method to obtain a LayoutInflater
                //from the given context
                //
                //The third param false, because we don't want to attach the list item view to the parent list view.
                //The'getContext()' parameter is defined in ArrayAdapter.
                listItemView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent, false);
            }
            //Get the object located at this position in the list. getItem() method from the super class ArrayAdapter
            final Word currentWord =  getItem(position);
    
            //Find the TextView in the list_item.xml layout with the id.
            //ArrayAdapter don't have the method of 'findViewById()',
            //so must have to use the method of 'View.findViewById()' to find the TextView
            TextView defaultTextView =  (TextView)listItemView.findViewById(R.id.default_text_view);
            defaultTextView.setText(currentWord.getDefaultTranslation());
    
            //Find the TextView in the list_item.xml layout with the id
            TextView miwokTextView = (TextView)listItemView.findViewById(R.id.miwok_text_view);
            miwokTextView.setText(currentWord.getMiwokTranslation());
    
            if (currentWord.checkImageResource()) { 
                //Find the ImageView in the list_item.xml layout with the id
                ImageView imageView = (ImageView)listItemView.findViewById(R.id.image_view);
                imageView.setImageResource(currentWord.getImageResourceId());
            }else{ 
                ImageView imageView = (ImageView)listItemView.findViewById(R.id.image_view);
                imageView.setVisibility(View.GONE);
            }
    
            RelativeLayout textLinearLayout = (RelativeLayout)listItemView.findViewById(R.id.text_relative_layout);
            textLinearLayout.setBackgroundResource(R.color.category_numbers);
    
    
    // textLinearLayout.setOnClickListener(new View.OnClickListener(){ 
    // public void onClick(final View view){ 
    // MediaPlayer mediaPlayer = MediaPlayer.create(getContext(), currentWord.getAudioResourceId());
    // Toast.makeText(view.getContext(), "Play", Toast.LENGTH_SHORT).show();
    // mediaPlayer.start();
    // mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){ 
    //
    // public void onCompletion(MediaPlayer mediaPlayer){ 
    // //Toast.makeText(view.getContext(),"I'm done!", Toast.LENGTH_SHORT).show();
    // mediaPlayer.release();
    // }
    // });
    // }
    // });
    
    
            return listItemView;
        }
    }