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xalexchen/LayoutTransChanging.java

Created September 17, 2013 03:44
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  1. xalexchen created this gist Sep 17, 2013.
    102 changes: 102 additions & 0 deletions LayoutTransChanging.java
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    import android.animation.LayoutTransition;
    import android.app.Activity;
    import android.content.Context;
    import android.os.Bundle;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Button;
    import android.widget.LinearLayout;
    import android.widget.LinearLayout.LayoutParams;

    /**
    * This example shows how to use LayoutTransition to animate simple changes in a layout
    * container.
    *
    * Watch the associated video for this demo on the DevBytes channel of developer.android.com
    * or on YouTube at https://www.youtube.com/watch?v=55wLsaWpQ4g.
    */
    public class LayoutTransChanging extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    final Button addButton =
    (Button) findViewById(R.id.addButton);
    final Button removeButton =
    (Button) findViewById(R.id.removeButton);
    final LinearLayout container =
    (LinearLayout) findViewById(R.id.container);
    final Context context = this;

    // Start with two views
    for (int i = 0; i < 2; ++i) {
    container.addView(new ColoredView(this));
    }

    addButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    // Adding a view will cause a LayoutTransition animation
    container.addView(new ColoredView(context), 1);
    }
    });

    removeButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    if (container.getChildCount() > 0) {
    // Removing a view will cause a LayoutTransition animation
    container.removeViewAt(Math.min(1, container.getChildCount() - 1));
    }
    }
    });

    // Note that this assumes a LayoutTransition is set on the container, which is the
    // case here because the container has the attribute "animateLayoutChanges" set to true
    // in the layout file. You can also call setLayoutTransition(new LayoutTransition()) in
    // code to set a LayoutTransition on any container.
    LayoutTransition transition = container.getLayoutTransition();

    // New capability as of Jellybean; monitor the container for *all* layout changes
    // (not just add/remove/visibility changes) and animate these changes as well.
    transition.enableTransitionType(LayoutTransition.CHANGING);
    }

    /**
    * Custom view painted with a random background color and two different sizes which are
    * toggled between due to user interaction.
    */
    private static class ColoredView extends View {

    private boolean mExpanded = false;

    private LayoutParams mCompressedParams = new LayoutParams(
    ViewGroup.LayoutParams.MATCH_PARENT, 50);

    private LayoutParams mExpandedParams = new LayoutParams(
    ViewGroup.LayoutParams.MATCH_PARENT, 200);

    private ColoredView(Context context) {
    super(context);
    int red = (int)(Math.random() * 128 + 127);
    int green = (int)(Math.random() * 128 + 127);
    int blue = (int)(Math.random() * 128 + 127);
    int color = 0xff << 24 | (red << 16) |
    (green << 8) | blue;
    setBackgroundColor(color);
    setLayoutParams(mCompressedParams);
    setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
    // Size changes will cause a LayoutTransition animation if the CHANGING
    // transition is enabled
    setLayoutParams(mExpanded ? mCompressedParams : mExpandedParams);
    mExpanded = !mExpanded;
    requestLayout();
    }
    });
    }
    }
    }