package com.example.aimee.buttontest;

import android.annotation.SuppressLint;

import android.graphics.Color;

import android.graphics.drawable.Drawable;

import android.support.v4.content.ContextCompat;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import android.view.KeyEvent;

public class MainActivity extends AppCompatActivity {

    TextView textview;//声明全局变量

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        final Button button1=(Button) findViewById(R.id.myButton1);

        final Button button2=(Button) findViewById(R.id.myButton2);

        final Button button3=(Button) findViewById(R.id.myButton3);

        textview=(TextView) findViewById(R.id.myTestView);

        final Drawable red_Drawable= ContextCompat.getDrawable(getBaseContext(),R.drawable.RED);

        final Drawable blue_Drawable= ContextCompat.getDrawable(getBaseContext(),R.drawable.BLUE);

        final Drawable yellow_Drawable= ContextCompat.getDrawable(getBaseContext(),R.drawable.YELLOW);

        button1.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                String str="You have clicked "+button1.getText().toString();

                textview.setText(str);

                if(textview.getBackground()!=red_Drawable){

                    textview.setBackground(red_Drawable);

                }

            }

        });

        button2.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                String str="You have clicked "+button2.getText().toString();

                textview.setText(str);

                if(textview.getBackground()!=blue_Drawable){

                    textview.setBackground(blue_Drawable);

                }

            }

        });

        button3.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                String str="You have clicked "+button3.getText().toString();

                textview.setText(str);

                if(textview.getBackground()!=yellow_Drawable){

                    textview.setBackground(yellow_Drawable);

                }

            }

        });

        }

    @SuppressLint("ResourceAsColor")

    public boolean onKeyUp(int keyCode, KeyEvent event){

        CharSequence Charseq="Change your color here!";

        textview.setText(Charseq);

        final Drawable white_Drawable= ContextCompat.getDrawable(getBaseContext(),R.drawable.WHITE);

        textview.setBackground(white_Drawable);

//        textview.setBackgroundColor(0xFFFFFFFF);

        return super.onKeyUp(keyCode,event);

    }

    public boolean onKeyDown(int keyCode,KeyEvent event){

        CharSequence Charseq="You have pressed ";

        Charseq=Charseq+"a key!";

        textview.setText(Charseq);

        return super.onKeyDown(keyCode,event);

    }

}

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <color name="colorPrimary">#3F51B5</color>

    <color name="colorPrimaryDark">#303F9F</color>

    <color name="colorAccent">#FF4081</color>

    <drawable name="BLUE">#FF0000FF</drawable>

    <drawable name="BLACK">#FF000000</drawable>

    <drawable name="RED">#FFFF0000</drawable>

    <drawable name="YELLOW">#FFFFFF00</drawable>

    <drawable name="WHITE">#FFFFFFFF</drawable>

</resources>

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity">

    <TextView

        android:id="@+id/myTestView"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:background="@drawable/WHITE"

        android:text="@string/hello"

        android:textSize="36sp"

        app:layout_constraintLeft_toLeftOf="parent"

        app:layout_constraintRight_toRightOf="parent" />

    <Button

        android:id="@+id/myButton1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/myButtonText1"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintLeft_toLeftOf="parent" />

    <Button

        android:id="@+id/myButton2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginEnd="8dp"

        android:layout_marginStart="8dp"

        android:text="@string/myButtonText2"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toStartOf="@+id/myButton3"

        app:layout_constraintStart_toEndOf="@+id/myButton1" />

    <Button

        android:id="@+id/myButton3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginEnd="8dp"

        android:text="@string/myButtonText3"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toEndOf="parent" />

</android.support.constraint.ConstraintLayout>