我試圖顯示一個隨機事實,並在事實發生變化時更改背景顏色。爲什麼隨機數會崩潰我的Android應用程序?
我使用MainActivity
上的一個隨機數做它,但只要我按下按鈕來生成並顯示該應用程序崩潰的隨機數。
這裏是鏈接到該項目在GitHub上: https://github.com/ishay1999/FunFacts
這裏是在logcat中所示的錯誤:
06-09 16:36:27.125 14551-14551/com.howtoevery.funfacts E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.howtoevery.funfacts, PID: 14551
android.content.res.Resources$NotFoundException: String resource ID #0x0
at android.content.res.Resources.getText(Resources.java:275)
at android.widget.TextView.setText(TextView.java:4261)
at com.howtoevery.funfacts.MainActivity$1.onClick(MainActivity.java:56)
at android.view.View.performClick(View.java:4763)
at android.view.View$PerformClick.run(View.java:19821)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5274)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
這裏是MainActivity.java
代碼:
package com.howtoevery.funfacts;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import java.util.Random;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// Creating the random
final Random rand = new Random();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView factLabel;
final Button showFactButton;
factLabel = (TextView) findViewById(R.id.fact);
final ViewGroup backGround = (RelativeLayout) findViewById(R.id.mainBackground);
showFactButton = (Button) findViewById(R.id.factButton);
View.OnClickListener myListener = new View.OnClickListener() {
int randomNumber;
@Override
public void onClick(View view) {
randomNumber = rand.nextInt(1); // randomNumber will be 0 or 1
switch (randomNumber) {
case 0: { // in case it is 0, show fact number 1 with green color
factLabel.setText(R.string.fact1);
backGround.setBackgroundColor(getResources().getColor(R.color.android_green));
showFactButton.setTextColor(getResources().getColor(R.color.android_green));
} break;
case 1: { // in case it is 1, show fact number 2 with orange color
factLabel.setText(R.string.fact2);
backGround.setBackgroundColor(getResources().getColor(R.color.orangish));
showFactButton.setTextColor(getResources().getColor(R.color.orangish));
} break;
}
factLabel.setText(randomNumber); // show the number generated with randomNumber, ONLY FOR DEBUG PURPOSES
}
};
showFactButton.setOnClickListener(myListener);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
我對應用程序的期望是,它會顯示不同的事實並更改顏色(現在,爲了調試,我希望看到文本更改s到生成的隨機數並且顏色已經改變)
爲什麼它不能像我期望的那樣工作?
根據該錯誤,您引用的是不存在的資源,並且它與隨機數無關。 – llogiq
@llogiq,什麼是不存在的資源? 'randomNumber'變量** do **存在。 –
@IshayFrenkel:*資源*,不可變。 –