最简单的方法如下
private void setupPasswordToggleView() {
final TextInputLayout textInputLayout = mRootView.findViewById(R.id.password);
// You can skip post-call and write directly the code which is inside run method.
// But to be safe (as toggle-view is child of TextInputLayout, post call
// has been added.
textInputLayout.post(new Runnable() {
@Override
public void run() {
CheckableImageButton passwordToggleView = textInputLayout.findViewById(R.id.text_input_password_toggle);
// passwordToggleView.toggle(); // Can not use as restricted to use same library group
// passwordToggleView.setChecked(true); // Can not use as restricted to use same library group
passwordToggleView.performClick();
}
});
}
现在让我解释一下答案
在查看TextInputLayout.java 的代码时，我发现design_text_input_password_icon.xml 的布局正在添加到TextInputLayout.java。下面是那个代码
private void updatePasswordToggleView() {
if (mEditText == null) {
// If there is no EditText, there is nothing to update
return;
}
if (shouldShowPasswordIcon()) {
if (mPasswordToggleView == null) {
mPasswordToggleView = (CheckableImageButton) LayoutInflater.from(getContext())
.inflate(R.layout.design_text_input_password_icon, mInputFrame, false);
mPasswordToggleView.setImageDrawable(mPasswordToggleDrawable);
mPasswordToggleView.setContentDescription(mPasswordToggleContentDesc);
mInputFrame.addView(mPasswordToggleView); // << HERE IS THAT
.........
}
现在下一个目标是找到design_text_input_password_icon.xml 并查找切换视图的ID。于是找到了布局design_text_input_password_icon.xml here，写成
18<android.support.design.widget.CheckableImageButton
19 xmlns:android="http://schemas.android.com/apk/res/android"
20 android:id="@+id/text_input_password_toggle"
21 android:layout_width="wrap_content"
22 android:layout_height="wrap_content"
23 android:layout_gravity="center_vertical|end|right"
24 android:background="?attr/selectableItemBackgroundBorderless"
25 android:minHeight="48dp"
26 android:minWidth="48dp"/>
我找到了该视图的 ID text_input_password_toggle，现在一切都很容易，只需在其视图组中找到该视图并对其执行操作即可。
另一种解决方案是迭代TextInputLayout 的孩子并检查它是否为CheckableImageButton，然后单击它。通过这种方式，该视图的 id 将不存在依赖关系，并且如果 Android 更改了视图的 id，我们的解决方案仍然可以工作。 （虽然它们在正常情况下不会更改视图的 id）。
private void setupPasswordToggleViewMethod2() {
final TextInputLayout textInputLayout = mRootView.findViewById(R.id.password);
textInputLayout.post(new Runnable() {
@Override
public void run() {
View toggleView = findViewByClassReference(textInputLayout, CheckableImageButton.class);
if (toggleView != null) {
toggleView.performClick();
}
}
});
}
其中findViewByClassReference(View rootView, Class<T> clazz) original utility class定义如下
public static <T extends View> T findViewByClassReference(View rootView, Class<T> clazz) {
if(clazz.isInstance(rootView)) {
return clazz.cast(rootView);
}
if(rootView instanceof ViewGroup) {
ViewGroup viewGroup = (ViewGroup) rootView;
for(int i = 0; i < viewGroup.getChildCount(); i++) {
View child = viewGroup.getChildAt(i);
T match = findViewByClassReference(child, clazz);
if(match != null) {
return match;
}
}
}
return null;
}