當列表有大量的數據,那麼我們的應用程序就會因應用程序內存不足而崩潰(因爲處理不當的行視圖)。 有解決和管理列表存儲雙向高效
使用converView
convertView - 老視圖如果可能的話再利用。注意:你應該在使用之前檢查這個視圖是非空的並且是合適的類型。如果無法將此視圖轉換爲顯示正確的數據,則此方法可以創建新視圖。
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
if(convertView == null) {
view = this.inflator.inflate(android.R.layout.simple_list_item_1, parent, false);
}
else {
view = convertView;
}
// remaining implementation
return view;
}
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使用RecyclerView
用於提供有限的窗口成一個大的數據集的柔性視圖。
添加RecyclerView到佈局
//A RecyclerView with some commonly used attributes
<android.support.v7.widget.RecyclerView
android:id="@+id/my_recycler_view"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
一旦你添加了一個RecyclerView小工具,你的佈局,獲得的句柄對象時,它連接到一個佈局管理器,並附加了一個適配器要顯示的數據:
public class MyActivity extends Activity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
// use a linear layout manager
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
// specify an adapter (see also next example)
mAdapter = new MyAdapter(myDataset);
mRecyclerView.setAdapter(mAdapter);
}
//... other code
}
適配器提供訪問您的數據集中的項目,創建視圖的項目,並在原來的產品沒有羅取代了一些新的數據項目視圖的內容可見的。下面的代碼示例示出了用於一個由字符串數組的數據集的簡單的實現使用的TextView窗口小部件顯示的:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private String[] mDataset;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public static class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView mTextView;
public ViewHolder(TextView v) {
super(v);
mTextView = v;
}
}
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(String[] myDataset) {
mDataset = myDataset;
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
TextView v = (TextView) LayoutInflater.from(parent.getContext())
.inflate(R.layout.my_text_view, parent, false);
// set the view's size, margins, paddings and layout parameters
...
ViewHolder vh = new ViewHolder(v);
return vh;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
holder.mTextView.setText(mDataset[position]);
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mDataset.length;
}
}
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Hope this will help one and all.
使用一個'ListView'。 – Luksprog