[英]bubble sort app with user input in android studio
我是android編程的新手,我嘗試通過在一個EditText中輸入數字來進行冒泡排序,然后將排序后的數字輸出到textview上。 單擊輸入按鈕后,程序意外停止。 請“告訴我什么地方出了問題”謝謝。
public class MainActivity extends AppCompatActivity {
TextView Result;
EditText Input;
Button ASButton;
int i,j,temp,num[];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ASButton = (Button) findViewById(R.id.button);
Input = (EditText) findViewById(R.id.editText);
Result = (TextView) findViewById(R.id.textView2);
ASButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
BubbleSort();
}
});
}
public void BubbleSort() {
Spannable spn = Input.getText();
for (int i = 0; i < spn.length(); i++){
num[i] = Integer.parseInt(""+spn.charAt(i));
}
for (i = 0; i < num.length; i++) {
for (j = i + 1; j < num.length; j++) {
if (num[i] > num[j]) {
temp = num[i];
num[i] = num[j];
num[j] = temp;
}
}
}
String result = "";
for (int i = 0; i < num.length; i++){
result += num[i] + " ";
}
Result.setText(result);
}
}
您沒有初始化num。 使用以下代碼
public void BubbleSort() {
Spannable spn = Input.getText();
num = new int[spn.length()];
int count = 0;
for (int i = 0; i < spn.length(); i++){
if((spn.charAt(i)+"").matches(".*\\d.*")){
num[i] = Integer.parseInt(""+spn.charAt(i));
count++;
}
}
for (i = 0; i < count; i++) {
for (j = i + 1; j < count; j++) {
if (num[i] > num[j]) {
temp = num[i];
num[i] = num[j];
num[j] = temp;
}
}
}
String result = "";
for (int i = 0; i < num.length; i++){
result += num[i] + " ";
}
Result.setText(result);
}
Spannable spn = Input.getText().toString;
而且你的泡泡so邏輯也錯了,正確的是這樣的
int temp = 0;
for (i = 0; i < num.length-1; i++) {
for (j = 0; j < num.length-1; j++) {
if (num[j] > num[j+1]) {
temp = num[j];
num[j] = num[j+1];
num[j+1] = temp;
}
}
}
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