通过添加RelativeLayout.LayoutParams，“应用程序不断停止”

Question

我是Android的新手，我正在关注thenewboston的教程系列。

目前正在观看视频34：动画和过渡。

此视频的目标是动画从左上方到右下角的按钮。

以下是 MainActivity 类的代码：

package com.example.jarno.a34_animations;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.transition.TransitionManager;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "debugMessage";

    ViewGroup mainLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG, "set activity_main");

        mainLayout = (ViewGroup) findViewById(R.id.mainLayout);

        // Click screen
        mainLayout.setOnTouchListener(
                new RelativeLayout.OnTouchListener() {
                    @Override
                    public boolean onTouch(View v, MotionEvent event) {
                        moveButton();
                        Log.i(TAG, "button click");
                        return true;
                    }
                }
        );
    }

    public void moveButton() {
        View animationButton = findViewById(R.id.animationButton);

        // Smooth transition
        TransitionManager.beginDelayedTransition(mainLayout);

        // Change position
        RelativeLayout.LayoutParams positionRules = new RelativeLayout.LayoutParams(
                RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        positionRules.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
        positionRules.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, RelativeLayout.TRUE);
        mainLayout.setLayoutParams(positionRules);

        // Change size
        ViewGroup.LayoutParams sizeRules = animationButton.getLayoutParams();
        sizeRules.width = 450;
        sizeRules.height = 300;
        animationButton.setLayoutParams(sizeRules);
    }
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/mainLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.jarno.a34_animations.MainActivity">

    <Button
        android:text="Button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"
        android:id="@+id/animationButton" />
</RelativeLayout>

通过评论此部分，应用程序不会崩溃。

// Change position
        RelativeLayout.LayoutParams positionRules = new RelativeLayout.LayoutParams(
                RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        positionRules.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
        positionRules.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, RelativeLayout.TRUE);
        mainLayout.setLayoutParams(positionRules);