我有一个活动，它从List中生成一个可滚动列表（让我们说一列）编程创建的按钮，这是一个sqlite表读取的结果，我的问题是随着List的增长（和所以按钮的数量）屏幕的初始绘画变得很慢（此刻需要3秒钟，有50个按钮可以绘制）所以我正在寻找解决方案。
起初我想过使用一个线程（runnable，handler或者其他什么是最好的），让我们说在For中创建一个新的线程迭代列表但是它没有工作（或者在至少我无法让它发挥作用）所以我的问题是下一个：
从列表＆lt;＆gt;开始这是创建大量可滚动按钮的最合适的方式，因此用户在访问屏幕时不会有这样的延迟。
Paginating可能是一种选择，但我想首先了解其他可能性并将其留作最后资源。
谢谢，下面是我的代码。
public static void createButtons(LinearLayout llContainer,
List<TestType> TestTypes, List<Test> Tests,
int buttonFontSize) {
Context oContext = llContainer.getContext();
String strTheme = TMAppearance.getThemeFromPreferences(oContext);
testMe = ((ApplicationConfiguration)oContext.getApplicationContext());
int callerActivity = TestTypes!=null ? 2 : 1;
if (TestTypes!=null || Tests!=null) {
int lCols = strTheme.equals(testMe.theme_vivid) ? 1 : 2;
//int sourceElementIndex = 0;
int originListSize = calculateOriginalListSize(callerActivity, TestTypes, Tests);
int lRows = (int) Math.ceil((double)originListSize/lCols);
List<String> aStartColors = TMUtils_ThemeVivid.generateStartColorArray(lRows, oContext);
List<String> aEndColors = TMUtils_ThemeVivid.generateEndColorArray(lRows, oContext);
for (i = 0; i < lRows; i++) {
LinearLayout outerButtonLayout = generateOuterButtonLayout(oContext);
for (j = 0; j < lCols; j++) {
final Thread r = new Thread() {
public void run() {
LinearLayout innerButtonLayout = generateInnerButtonLayout(oContext);
outerButtonLayout.addView(innerButtonLayout, j);
if (sourceElementIndex<originListSize){
final TMButton oButton = new TMButton(oContext);
if (callerActivity==1) { //testMenu
setTestMenuButtonSettings(oButton, sourceElementIndex, Tests);
} else {
if (callerActivity==2) { //testTypeMenu
setTestTypeMenuButtonSettings(oButton, sourceElementIndex, TestTypes);
}
}
if (strTheme.equals(testMe.theme_vivid)){
oButton.fontSize = buttonFontSize;
oButton.gradientStartColor = aStartColors.get(i);
oButton.gradientEndColor = aEndColors.get(i);
}else{
if (strTheme.equals(testMe.theme_purple)){
oButton.gradientStartColor = testMe.btnStartColor_purple;
oButton.gradientEndColor = testMe.btnEndColor_purple;
}
}
configureButton(oButton, callerActivity);
oButton.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
Context oContext = v.getContext();
TMButton oButton = (TMButton) v;
int callerActivity = Integer.valueOf(v.getTag().toString().split("@")[0]);
String sourceId = String.valueOf(v.getTag().toString().split("@")[1]);
if(event.getAction() == MotionEvent.ACTION_DOWN) { //pressed
setButtonPressed(oButton);
TMSound.playButtonSound(oContext);
} else if (event.getAction() == MotionEvent.ACTION_UP) { //released
setButtonReleased(oButton);
startTargetActivity(callerActivity, sourceId, oContext);
}
return true;
}
});
TMAppearance.doButtonAnimation(oContext, oButton, i);
innerButtonLayout.addView(oButton);
sourceElementIndex++;
}
}
};
r.run();
}
llContainer.addView(outerButtonLayout);
}
}
}
答案 0 :(得分：0)
0X0nosugar 是正确的。 RecycleView将提供更好的性能，但许多初学者在实现它时遇到更多困难，只有50个按钮的性能应该不是真正的问题。虽然我通常喜欢遵守“使用最佳可用解决方案”这一规则，但我认为学习如何实施ListView仍然是合适的。所以...
您需要创建自定义适配器：
public class MyListDataAdapter extends ArrayAdapter<MyListData> {
private static final String TAG = "MyListDataAdapter";
public MyListDataAdapter(Context context, ArrayList<MyListData> data) {
super(context, 0, data);
}
@Override
public View getView(int position, View convertView, ViewGroup parent){
final MyListData data = getItem(position);
if(convertView == null){
convertView = LayoutInflater.from(getContext()).inflate(R.layout.edit_list_item, parent, false);
}
// Add a TextView if you need one
final TextView tvName = (TextView) convertView.findViewById(R.id.tvName);
Button btnEditTicketHolder = (Button) convertView.findViewById(R.id.btnEdit);
btnEditTicketHolder.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
long userId = data.getUserId();
String fName = data.getFirstName();
Intent intent = new Intent(getContext(), EditActivity.class);
intent.putExtra("userId", userId);
intent.putExtra("fName", fName);
getContext().startActivity(intent);
}
});
String name = data.getFirstName();
tvName.setText(name);
return convertView;
}
}
现在您需要MyListData类来保存数据：
public class MyListData {
// Add more as you need
private long userId;
private String firstName;
public MyListData(){
}
public void setFirstName(String name){ this.firstName = name; }
public void setUserId(long id){ this.userId = id; }
public String getFirstName(){ return this.firstName; }
public long getUserId(){ return this.userId; }
}
您的自定义ListView布局可能如下所示：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
>
<TextView
android:id="@+id/tvName"
android:text="With Whom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
>
<Button
android:id="@+id/btnEdit"
android:layout_width="wrap_content"
android:layout_height="40dp"
android:paddingRight="10dp"
android:paddingLeft="10dp"
android:text="Edit"
android:backgroundTint="@color/colorAccent"
android:focusable="false"
/>
</LinearLayout>
</RelativeLayout>
在您的活动中（例如，在onCreate()方法中）ListView，您需要填充ListView的数据。这应该在UI线程上不
ArrayList<MyListData> arrayListData = new ArrayList<MyListData>();
MyListDataAdapter adapter = new MyListDataAdapter(this, arrayListData);
for (MyListData g : result) {
adapter.add(g);
}
mLstMy.setAdapter(adapter);
同样在要维护ListView的活动中，如果您需要，请设置一些onClick事件处理程序：
（我发现ListView的一个小优势是onClick事件比RecycleView更容易实现
mMyLst = (ListView) findViewById(lstMy);
mMyLst.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long l) {
MyListData data = (MyListData) parent.getItemAtPosition(position);
selectedName = data.getName();
Intent intent = new Intent(ShowListDataActivity.this, MainActivity.class);
startActivity(intent);
}
});
mMyLst.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l) {
MyListData data = (MyistData) adapterView.getItemAtPosition(i);
selectedName = data.getFirstName();
selectedTicketPosition = i;
// removeValue is my own method for removing an entry from the
// list MyListData and then call adapter.notifyDataSetChanged();
removeValue(i);
return true;
}
});