ListView(1)+intent獲得應用

                        ***ListView初步基礎***

在底部增加視圖addFooterView(view);

最簡單的listView點擊每個item跳轉界面

mListView = (ListView) findViewById(R.id.list_view_demo);
ArrayList<ActivityItem> activityItems = new ArrayList<>();
activityItems.add(new ActivityItem("1. 應用列表", AppListActivity.class));
activityItems.add(new ActivityItem("2. 異步請求數據列表", RequestDataActivity.class));
activityItems.add(new ActivityItem("3. 模仿IM聊天佈局", ChatActivity.class));
mListView.setAdapter(new MainListAdapter(MainActivity.this,activityItems ));

getinfo方法

        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        return getPackageManager().queryIntentActivities(mainIntent, 0);

在adapter裏面獲取當前視圖

LayoutInflater layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View headerView = layoutInflater.inflate(R.layout.header_list_demo, null);
viewHolder.nameTextView = (TextView) convertView.findViewById(R.id.title_text_view);

在adapter裏面重複利用ViewHolder

if(convertView == null){
        viewHolder = new ViewHolder();
        convertView = layoutInflater.inflate(R.layout.item_demo_list, null);
                // 獲取控件
        viewHolder.nameTextView = (TextView) convertView.findViewById(R.id.title_text_view);
        viewHolder.avatarImageView = (ImageView)convertView.findViewById(R.id.icon_image_view);
        convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }

獲取應用名稱圖片

viewHolder.nameTextView.setText(mInfos.get(position).activityInfo.loadLabel(mContext.getPackageManager()));
            viewHolder.avatarImageView.setImageDrawable(mInfos.get(position).activityInfo.loadIcon(mContext.getPackageManager()));

在getView裏面設置每個item的點擊事件

convertView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    ResolveInfo info = mInfos.get(position);

                    //該應用的包名
                    String pkg = info.activityInfo.packageName;
                    //應用的主activity類
                    String cls = info.activityInfo.name;

                    ComponentName componet = new ComponentName(pkg, cls);

                    Intent intent = new Intent();
                    intent.setComponent(componet);
                    startActivity(intent);
                }
            });

全部代碼

public class AppListActivity extends AppCompatActivity{

    private ListView mListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (ListView) findViewById(R.id.list_view_demo);
        LayoutInflater layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View headerView = layoutInflater.inflate(R.layout.header_list_demo, null);
        mListView.addHeaderView(headerView);
        List<ResolveInfo> infos = getAppInfos();
        mListView.setAdapter(new AppListAdapter(this, infos));
    }

    private List<ResolveInfo> getAppInfos() {
        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        return getPackageManager().queryIntentActivities(mainIntent, 0);
    }

    public class AppListAdapter extends BaseAdapter{

        private Context mContext;
        private List<ResolveInfo> mInfos;

        public AppListAdapter(Context context, List<ResolveInfo> infos) {
            mContext = context;
            mInfos = infos;
        }

        @Override
        public int getCount() {
            return mInfos.size();
        }

        @Override
        public Object getItem(int position) {
            return mInfos.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            LayoutInflater layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            if(convertView == null){
                viewHolder = new ViewHolder();
                convertView = layoutInflater.inflate(R.layout.item_demo_list, null);
                // 獲取控件
                viewHolder.nameTextView = (TextView) convertView.findViewById(R.id.title_text_view);
                viewHolder.avatarImageView = (ImageView) convertView.findViewById(R.id.icon_image_view);
                convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }
            // 和數據之間進行綁定
            viewHolder.nameTextView.setText(mInfos.get(position).activityInfo.loadLabel(mContext.getPackageManager()));
            viewHolder.avatarImageView.setImageDrawable(mInfos.get(position).activityInfo.loadIcon(mContext.getPackageManager()));

            convertView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    ResolveInfo info = mInfos.get(position);

                    //該應用的包名
                    String pkg = info.activityInfo.packageName;
                    //應用的主activity類
                    String cls = info.activityInfo.name;

                    ComponentName componet = new ComponentName(pkg, cls);

                    Intent intent = new Intent();
                    intent.setComponent(componet);
                    startActivity(intent);
                }
            });
            return convertView;
        }

        class ViewHolder {
            ImageView avatarImageView;
            TextView nameTextView;
        }
    }