作业

1.程序代码

图片随着鼠标移动位置，并显示出当前位置的坐标信息。 当用户点击退出按钮，给出提示信息：“再按一次退出程序”

运行代码

---

package com.example.flower2;

import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
private ImageView LH;
private long time;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LH = (ImageView) findViewById(R.id.LH);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction()==MotionEvent.ACTION_DOWN){
String pos="";
float x=event.getX();
float y=event.getY();
LH.setPadding((int)x-100,(int)y-300,0,0);
pos="x轴坐标"+x+"y轴坐标"+y;
Toast.makeText(this,pos,Toast.LENGTH_SHORT).show();
}
return super.onTouchEvent(event);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LH = (ImageView) findViewById(R.id.LH);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction()==MotionEvent.ACTION_DOWN){
String pos="";
float x=event.getX();
float y=event.getY();
LH.setPadding((int)x-100,(int)y-300,0,0);
pos="x轴坐标"+x+"y轴坐标"+y;
Toast.makeText(this,pos,Toast.LENGTH_SHORT).show();
}
return super.onTouchEvent(event);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getKeyCode()==KeyEvent.KEYCODE_BACK){
exit();
return false;
}
return super.onKeyDown(keyCode, event);
}
void exit(){
if(System.currentTimeMillis()-time>2000){
Toast.makeText(this,"再点一次退出程序!",Toast.LENGTH_SHORT).show();
time=System.currentTimeMillis();
}else {
finish();
}
}
}
***

2.图片选择

1. 综合使用TextView,ImageView,RadioButton控件实现一个图片选择器，通过勾选相应的名称显示相应的图片。
   具体要求如下：
   a) 使用滚动字幕显示标题“请选择你喜欢的”
   b) 使用RadioGroup 和RadioButton 创建两行三列的单选按钮；
   c) 当用户选中某一名称，在页面上显示该种图片

程序代码，实现界面布置

分为两组RB实现选择按钮

***

***

2.运行代码

---

public class MainActivity extends AppCompatActivity {
private ImageView tp;
private TextView text;
private RadioGroup bt;
private RadioGroup bt2;
private RadioButton lh;
private RadioButton wyf;
private RadioButton cwt;
private RadioButton hg;
private RadioButton lzx;
private RadioButton wyh;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tp=(ImageView)findViewById(R.id.tp);
bt=(RadioGroup) findViewById(R.id.bt);
bt2=(RadioGroup) findViewById(R.id.bt2);
lh=(RadioButton)findViewById(R.id.lh);
wyf=(RadioButton)findViewById(R.id.wyf);
cwt=(RadioButton)findViewById(R.id.cwt);
hg=(RadioButton)findViewById(R.id.hg);
lzx=(RadioButton)findViewById(R.id.lzx);
wyf=(RadioButton) findViewById(R.id.wyh);
lh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (lh.isChecked()){
tp.setImageResource(R.drawable.a);
}
}
});
wyf.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (wyf.isChecked()){
tp.setImageResource(R.drawable.b);
}
}
});
cwt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (cwt.isChecked()){
tp.setImageResource(R.drawable.c);
}
}
});
lzx.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (lzx.isChecked()){
tp.setImageResource(R.drawable.d);
}
}
});
lh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (hg.isChecked()){
tp.setImageResource(R.drawable.e);
}
}
});
wyh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (wyh.isChecked()){
tp.setImageResource(R.drawable.f);
}
}
});
}
void bt(){
lh.setChecked(false);
wyf.setChecked(false);
cwt.setChecked(false);
}
void bt2() {
lzx.setChecked(false);
hg.setChecked(false);
wyh.setChecked(false);
}
}
***

设置6个监听事件完成代码实现与按钮的选择