我想使用约束布局程序化地创建一个TextView(或任何其他视图)。这个textView在XML中看起来像这样:
<TextView
android:id="@+id/textView_Test"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Test "
android:textSize="19sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintVertical_bias="0.16"
app:layout_constraintHorizontal_bias="0.02"
app:layout_constraintTop_toTopOf="parent" />
所以它应该在所有方面都受到父级的限制,然后我可以使用偏置参数来动态更改它的位置。我该如何实现这一点?我查看了这里给出的答案 ConstraintLayout: change constraints programmatically 但是那里的对象没有受到父级的限制,并且没有使用垂直和水平偏差来实现我想要的动态定位。有什么想法能否在Fragment中实现这个功能(我使用Single-Activity Multiple-Fragments方法)?
更新: 我现在可以在约束布局中编程方式地插入自定义视图(而不是TextView)。但是,使用代码
constraintSet.setHorizontalBias(view.getId(), 0.56f);
来设置方向没有任何效果(无论使用哪些数字)。自定义视图始终位于左上角。这里可以看到整个片段的代码(我标注了重要部分):
public class Test extends Fragment implements Runnable {
/*
Game variables
*/
public static final int DELAY_MILLIS = 100;
public static final int TIME_OF_A_LEVEL_IN_SECONDS = 90;
private int currentTimeLeftInTheLevel_MILLIS;
private Handler handler = new Handler();
private FragmentGameBinding binding;
private boolean viewHasBeenCreated = false;
public Test() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
binding = FragmentGameBinding.inflate(inflater, container, false);
container.getContext();
viewHasBeenCreated = true;
startRound();
return binding.getRoot();
}
public void startRound () {
currentTimeLeftInTheLevel_MILLIS =TIME_OF_A_LEVEL_IN_SECONDS * 1000;
updateScreen();
handler.postDelayed(this, 1000);
}
private void updateScreen() {
binding.textViewTimeLeftValue.setText("" + currentTimeLeftInTheLevel_MILLIS/1000);
/*
IMPORTANT PART: This should create a simple custom UI element
*/
View view = new View(getActivity());
view.setLayoutParams(new ViewGroup.LayoutParams(200, 200));
Drawable dr = ContextCompat.getDrawable(getActivity(),R.drawable.light_bulb_layer_list);
view.setBackground(dr);
view.setId(View.generateViewId());
ConstraintLayout constraintLayout = binding.constraintLayout;
ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(constraintLayout);
constraintSet.connect(view.getId(),ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID,ConstraintSet.BOTTOM,0);
constraintSet.connect(view.getId(),ConstraintSet.TOP,ConstraintSet.PARENT_ID ,ConstraintSet.TOP,0);
constraintSet.connect(view.getId(),ConstraintSet.LEFT,ConstraintSet.PARENT_ID ,ConstraintSet.LEFT,0);
constraintSet.connect(view.getId(),ConstraintSet.RIGHT,ConstraintSet.PARENT_ID ,ConstraintSet.RIGHT,0);
constraintSet.setHorizontalBias(view.getId(), 0.56f);
constraintSet.setVerticalBias(view.getId(), 0.5f);
constraintSet.applyTo(constraintLayout);
constraintLayout.addView(view);
}
private void countDownTime(){
currentTimeLeftInTheLevel_MILLIS = currentTimeLeftInTheLevel_MILLIS -DELAY_MILLIS;
updateScreen();
}
@Override
public void run() {
if(viewHasBeenCreated) {
countDownTime();
}
有没有想法,为什么在约束布局中设置水平或垂直方向时没有任何效果?
constraintLayout.addView(view);
之后非常末尾设置constraintSet.clone(constraintLayout);
时,什么也没有改变。自定义视图位于左上角,并且在约束布局中设置水平或垂直方向仍然没有任何效果。我还尝试了设置constraintSet.applyTo(constraintLayout);
并更改了一些语句的顺序。要么什么都不会发生(更改方向没有任何效果),要么自定义视图覆盖整个显示屏。 - VanessaFaddView()
移动到克隆之前。你希望添加的视图 ID 被约束集知道。 - Cheticamp