我正在创建我的第一个应用程序,当我调试应用程序时,它显示错误说“错误:(33,55)错误:找不到符号变量next_level_button ”和“错误:(43,44)错误:无法找到符号变量级别“请为此提供解决方案。 :)
这是代码
package com.example.aman.myapplication;
import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.InterstitialAd;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
// Remove the below line after defining your own ad unit ID.
private static final String TOAST_TEXT = "Test ads are being shown. "
+ "To show live ads, replace the ad unit ID in res/values/strings.xml with your own ad unit ID.";
private static final int START_LEVEL = 1;
private int mLevel;
private Button mNextLevelButton;
private InterstitialAd mInterstitialAd;
private TextView mLevelTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create the next level button, which tries to show an interstitial when clicked.
mNextLevelButton = ((Button) findViewById(R.id.next_level_button));
mNextLevelButton.setEnabled(false);
mNextLevelButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
showInterstitial();
}
});
// Create the text view to show the level number.
mLevelTextView = (TextView) findViewById(R.id.level);
mLevel = START_LEVEL;
// Create the InterstitialAd and set the adUnitId (defined in values/strings.xml).
mInterstitialAd = newInterstitialAd();
loadInterstitial();
// Toasts the test ad message on the screen. Remove this after defining your own ad unit ID.
Toast.makeText(this, TOAST_TEXT, Toast.LENGTH_LONG).show();
}
@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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private InterstitialAd newInterstitialAd() {
InterstitialAd interstitialAd = new InterstitialAd(this);
interstitialAd.setAdUnitId(getString(R.string.interstitial_ad_unit_id));
interstitialAd.setAdListener(new AdListener() {
@Override
public void onAdLoaded() {
mNextLevelButton.setEnabled(true);
}
@Override
public void onAdFailedToLoad(int errorCode) {
mNextLevelButton.setEnabled(true);
}
@Override
public void onAdClosed() {
// Proceed to the next level.
goToNextLevel();
}
});
return interstitialAd;
}
private void showInterstitial() {
// Show the ad if it's ready. Otherwise toast and reload the ad.
if (mInterstitialAd != null && mInterstitialAd.isLoaded()) {
mInterstitialAd.show();
} else {
Toast.makeText(this, "Ad did not load", Toast.LENGTH_SHORT).show();
goToNextLevel();
}
}
private void loadInterstitial() {
// Disable the next level button and load the ad.
mNextLevelButton.setEnabled(false);
AdRequest adRequest = new AdRequest.Builder()
.setRequestAgent("android_studio:ad_template").build();
mInterstitialAd.loadAd(adRequest);
}
private void goToNextLevel() {
// Show the next level and reload the ad to prepare for the level after.
mLevelTextView.setText("Level " + (++mLevel));
mInterstitialAd = newInterstitialAd();
loadInterstitial();
}
}
答案 0 :(得分:-1)
使用您的按钮名称进行更改:
mNextLevelButton = (Button) findViewById(R.id.your_button_name);