我是Android Studio的新手。我经过了正式的developer.android.com培训,因此决定创建一个名为Grocery +的新的简单应用程序,用户可以在其中输入特定商品的价格和数量,并且该应用程序将显示总金额。
我已经完成了所有基于UI的工作,然后今天我转向编程。我是一位经验丰富的Java程序员。我还完成了所有工作,但:
1- 尝试输入第一个时,我的应用程序崩溃。
然后,我必须先输入其他任何值,然后再输入第一个值。
2- ,即使在遭到上述黑客攻击后,我的应用也未在“总计”中显示任何内容
请帮助:(((
package com.amostrone.akash.grocery;
import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
static int Quantity[] = new int[4];
static float Price[] = new float[4];
public static double total=0;
static TextView txtValue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtValue = (TextView) findViewById(R.id.txtExample);
}
/////////// QUANTITY
public void input_Quantity(View view) {
EditText x = (EditText) findViewById(R.id.editQuantity);
calc();
}
public void input_Quantity2(View view) {
EditText x = (EditText) findViewById(R.id.editQuantity2);
Quantity[1] = Integer.parseInt(x.toString());
calc();
}
public void input_Quantity3(View view) {
EditText x = (EditText) findViewById(R.id.editQuantity3);
Quantity[2] = Integer.parseInt(x.toString());
calc();
}
public void input_Quantity4(View view) {
EditText x = (EditText) findViewById(R.id.editQuantity4);
Quantity[3] = Integer.parseInt(x.toString());
calc();
}
public void input_Quantity5(View view) {
EditText x = (EditText) findViewById(R.id.editQuantity5);
Quantity[4] = Integer.parseInt(x.toString());
calc();
}
/////////////// Quantity
////////////// Price
public void input_Price(View view) {
EditText x = (EditText) findViewById(R.id.editPrice);
Price[0] = Float.parseFloat(x.toString());
calc();
}
public void input_Price2(View view) {
EditText x = (EditText) findViewById(R.id.editPrice2);
Price[1] = Float.parseFloat(x.toString());
calc();
}
public void input_Price3(View view) {
EditText x = (EditText) findViewById(R.id.editPrice3);
Price[2] = Float.parseFloat(x.toString());
calc();
}
public void input_Price4(View view) {
EditText x = (EditText) findViewById(R.id.editPrice4);
Price[3] = Float.parseFloat(x.toString());
calc();
}
public void input_Price5(View view) {
EditText x = (EditText) findViewById(R.id.editPrice5);
calc();
}
///////////// Price
/////////////// Calculate
public static void calc()
{
for(int i=0;i<=4;i++)
total += (Quantity[i] * Price[i]);
String str = Double.toString(total);
txtValue.setText(str);
}
////////////// Calculate }
最佳答案
查看您的代码,看来您正在触发EditText
值获取和click事件的计算(通过xml)。这样无法正常工作,因为会立即触发它们。解决此问题的方法之一是采用TextWatcher
路由。检查以下构建的代码,我也对其进行了重构(现在应该更不容易出现内存泄漏):
public double mTotal;
private TextView mTextView;
private EditText[] mQuantityEditTexts = new EditText[5];
private EditText[] mPriceEditTexts = new EditText[5];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextView = (TextView) findViewById(R.id.txtExample);
mQuantityEditTexts[0] = (EditText) findViewById(R.id.editQuantity);
mQuantityEditTexts[1] = (EditText) findViewById(R.id.editQuantity2);
mQuantityEditTexts[2] = (EditText) findViewById(R.id.editQuantity3);
mQuantityEditTexts[3] = (EditText) findViewById(R.id.editQuantity4);
mQuantityEditTexts[4] = (EditText) findViewById(R.id.editQuantity5);
mPriceEditTexts[0] = (EditText) findViewById(R.id.editPrice);
mPriceEditTexts[1] = (EditText) findViewById(R.id.editPrice2);
mPriceEditTexts[2] = (EditText) findViewById(R.id.editPrice3);
mPriceEditTexts[3] = (EditText) findViewById(R.id.editPrice4);
mPriceEditTexts[4] = (EditText) findViewById(R.id.editPrice5);
for (int i = 0; i < 5; i++) {
mQuantityEditTexts[i].addTextChangedListener(mTextWatcher);
mPriceEditTexts[i].addTextChangedListener(mTextWatcher);
}
}
private TextWatcher mTextWatcher = new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
calc();
}
@Override
public void afterTextChanged(Editable s) {
}
};
public void calc()
{
try {
for (int i = 0; i <= 4; i++)
mTotal += Integer.parseInt(mQuantityEditTexts[i].getText().toString()) *
Double.parseDouble(mPriceEditTexts[i].getText().toString());
String str = Double.toString(mTotal);
mTextView.setText(str);
} catch (NumberFormatException e) {
Toast.makeText(this, "WTF! Enter valid numbers!", Toast.LENGTH_SHORT).show();
}
}
关于java - 输入数值以编辑文本时,我的应用程序崩溃了,并且它没有显示正确的值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39304171/