src/android/src/com/google/android/inputmethod/japanese/ConversionCandidateWordContainerView.java

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package org.mozc.android.inputmethod.japanese;

import org.mozc.android.inputmethod.japanese.CandidateView.ConversionCandidateWordView;
import org.mozc.android.inputmethod.japanese.resources.R;
import org.mozc.android.inputmethod.japanese.ui.ConversionCandidateLayouter;
import com.google.common.base.Preconditions;

import android.content.Context;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.ToggleButton;

/**
 * A container (ViewGroup) of candidate word view and input frame fold button.
 *
 * The fold button should be laid out based on candidate word view's internal state
 * (candidate layouter), which is determined at layout flow.
 * The initial implementation sets the button's layout parameter from onLayout method
 * but setting layout parameter on layout flow (e.g. in onLayout() and onSizeChanged())
 * causes unexpected behavior (e.g. infinite loop).
 * This class is introduced to solve this issue.
 *
 * This class is a simple ViewGroup. The layout algorithm is fixed (layout .xml file doesn't affect
 * anything) so {@link #onMeasure(int, int)} is omitted.
 * First, candidate word view fills all the view.
 * Second, input frame fold button is laid out based on ConversionCandidateLayouter's state
 * (which cannot be accessed from standard view layouters. This is the reason why this class is
 * introduced).
 * The layout flow descibed above doesn't depend on {@link android.view.ViewGroup.LayoutParams}
 * we can avoid from unexpected behavior.
 */
public class ConversionCandidateWordContainerView extends ViewGroup {

  private float foldingIconSize;

  public ConversionCandidateWordContainerView(
      Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }

  public ConversionCandidateWordContainerView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

  public ConversionCandidateWordContainerView(Context context) {
    super(context);
  }

  void setCandidateTextDimension(float candidateTextSize) {
    Preconditions.checkArgument(candidateTextSize > 0);

    foldingIconSize = candidateTextSize
        + getResources().getDimension(R.dimen.candidate_vertical_padding_size) * 2;
  }

  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    // Note: Don't use getMeasuredHeight/Width for this and children because #onMeasure
    //       is omitted so they return invalid value.
    ConversionCandidateWordView candidateWordView =
        ConversionCandidateWordView.class.cast(findViewById(R.id.candidate_word_view));
    candidateWordView.layout(left, top, right, bottom);
    ToggleButton inputFrameFoldButton =
        ToggleButton.class.cast(findViewById(R.id.input_frame_fold_button));
    if (inputFrameFoldButton.getVisibility() != VISIBLE) {
      return;
    }

    ConversionCandidateLayouter layouter = candidateWordView.getCandidateLayouter();
    float topMargin = (layouter.getRowHeight() - foldingIconSize) / 2;
    float rightMargin = (layouter.getChunkWidth() - foldingIconSize) / 2;
    inputFrameFoldButton.layout((int) (right - rightMargin - foldingIconSize),
                                (int) (top + topMargin),
                                (int) (right - rightMargin),
                                (int) (top + topMargin + foldingIconSize));
  }
}