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我試圖製作一個應用程序，它使用Eclipse在Java中每4秒從一組4種顏色中選取隨機顏色。我唯一真正的編程經驗是在flash中使用actionscript，並且在獲得我想要的結果時遇到了一些問題。 我跟隨了一些基礎知識的教程，並且足夠了解編碼，以便更改它足以接近我想要的內容，但目前它只能按照目前的方式循環。隨機顏色每4秒更換一組顏色 - Android應用程序
MainActivity.java
package com.example.androidcountdowntimer;
import com.example.androidcountdowntimer.SpotView.SpotCallBack;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity
implements SpotCallBack{
TextView myState, myCounter;
Button btnStart;
SpotView mySpotView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mySpotView = (SpotView)findViewById(R.id.myspotview);
mySpotView.setCallback(this);
myState = (TextView) findViewById(R.id.mystate);
myCounter = (TextView) findViewById(R.id.mycounter);
btnStart = (Button) findViewById(R.id.start);
btnStart.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mySpotView.startRun();
}
});
}
@Override
public void cb_onTick(String msg) {
myCounter.setText("Milliseconds: " + msg);
}
@Override
public void cb_onFinish(String msg) {
myState.setText(msg);
}
}
SpotView.java
package com.example.androidcountdowntimer;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.CountDownTimer;
import android.util.AttributeSet;
import android.view.View;
public class SpotView extends View{
//used to pass back something to MainActivity
interface SpotCallBack {
void cb_onTick(String msg);
void cb_onFinish(String msg);
}
SpotCallBack spotCallback;
CountDownTimer countDownTimer;
int state;
final static int STATE_IDLE = 0;
final static int STATE_RED = 1;
final static int STATE_GREEN = 2;
final static int STATE_BLUE = 3;
final static int STATE_YELLOW = 4;
Paint paintRed, paintGreen, paintBlue, paintYellow;
public SpotView(Context context) {
super(context);
init();
}
public SpotView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public SpotView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init(){
state = STATE_IDLE;
paintRed = new Paint();
paintRed.setColor(Color.RED);
paintRed.setStrokeWidth(1);
paintRed.setStyle(Paint.Style.FILL);
paintGreen = new Paint();
paintGreen.setColor(Color.GREEN);
paintGreen.setStrokeWidth(1);
paintGreen.setStyle(Paint.Style.FILL);
paintBlue = new Paint();
paintBlue.setColor(Color.BLUE);
paintBlue.setStrokeWidth(1);
paintBlue.setStyle(Paint.Style.FILL);
paintYellow = new Paint();
paintYellow.setColor(Color.YELLOW);
paintYellow.setStrokeWidth(1);
paintYellow.setStyle(Paint.Style.FILL);
}
public void setCallback(SpotCallBack cb){
spotCallback = cb;
}
public void startRun(){
state = STATE_RED;
if(countDownTimer!=null){
countDownTimer.cancel();
}
countDownTimer = new CountDownTimer(4000, 500) {
@Override
public void onTick(long millisUntilFinished) {
spotCallback.cb_onTick(String.valueOf(millisUntilFinished));
}
@Override
public void onFinish() {
if(state == STATE_RED){
state = STATE_GREEN;
spotCallback.cb_onFinish("GREEN");
}else if(state == STATE_GREEN){
state = STATE_BLUE;
spotCallback.cb_onFinish("BLUE");
}else if(state == STATE_BLUE){
state = STATE_YELLOW;
spotCallback.cb_onFinish("YELLOW");
}else if(state == STATE_YELLOW){
state = STATE_RED;
spotCallback.cb_onFinish("RED");
}
countDownTimer.start();
invalidate();
}
};
countDownTimer.start();
spotCallback.cb_onFinish("RED");
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
float w = getWidth();
float h = getHeight();
if(state == STATE_RED){
canvas.drawCircle(w/2, h/2, 400, paintRed);
}else if(state == STATE_GREEN){
canvas.drawCircle(w/2, h/2, 400, paintGreen);
}else if(state == STATE_BLUE){
canvas.drawCircle(w/2, h/2, 400, paintBlue);
}else if(state == STATE_YELLOW){
canvas.drawCircle(w/2, h/2, 400, paintYellow);
}
}
}
activity_main.xml中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
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"
android:orientation="vertical"
tools:context="com.example.androidcountdowntimer.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="Tynes Timer Thing"
android:textStyle="bold"
android:textSize="24sp" />
<Button
android:id="@+id/start"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Start CountDownTimer" />
<TextView
android:id="@+id/mystate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:textSize="24sp" />
<TextView
android:id="@+id/mycounter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:textSize="24sp" />
<com.example.androidcountdowntimer.SpotView
android:id="@+id/myspotview"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
所以他們的方式我試圖使顏色的變化是隨機通過存儲用於狀態的顏色作爲變量，然後試圖使用該變量來創建當前代碼的一部分只是通過一組狀態動態喜歡的運行：
String[] colours = {"STATE_RED", "STATE_GREEN", "STATE_BLUE", "STATE_YELLOW"};
int idx = new Random().nextInt(colours.length);
String random = (colors[idx]);
，並以此來嘗試設置在ELSEIF
state = random;
的狀態，但我只是不斷得到紅色X和錯誤在我的代碼和斜面弄清楚如何在java中隨機改變狀態。
任何幫助和/或建議將不勝感激。
感謝， 利亞姆
也許你有一些其他的字符串數組命名爲「顏色」，它只有紅色的狀態.....什麼是錯誤？ –
對不起，我不是很清楚，現在問題解決了！無論如何感謝：D – user3773772